Speedup test_shape.rb

Many tests start by exhausting all shapes, which is a slow process.
By exposing a method to directly move the bump allocator forward
we cut test runtime in half.

Before:
```
Finished tests in 1.544756s
```

After:
```
Finished tests in 0.759733s,
```

1 files changed, 22 insertions, 114 deletions

diff --git a/test/ruby/test_shapes.rb b/test/ruby/test_shapes.rb
index 57c97d9031..cf1885bbdf 100644
--- a/test/ruby/test_shapes.rb
+++ b/test/ruby/test_shapes.rb
@@ -191,12 +191,7 @@ class TestShapes < Test::Unit::TestCase
         attr_reader :very_unique
       end
 
-      obj = Object.new
-      i = 0
-      while RubyVM::Shape.shapes_available > 0
-        obj.instance_variable_set(:"@a#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes
 
       (RubyVM::Shape::SHAPE_MAX_VARIATIONS * 2).times do
         TooComplex.new.instance_variable_set(:"@unique_#{_1}", 1)
@@ -216,13 +211,7 @@ class TestShapes < Test::Unit::TestCase
     assert_separately([], "#{<<~"begin;"}\n#{<<~'end;'}")
     begin;
       class Hi; end
-
-      obj = Hi.new
-      i = 0
-      while RubyVM::Shape.shapes_available > 2
-        obj.instance_variable_set(:"@a#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes(3)
 
       obj = Hi.new
       i = 0
@@ -243,26 +232,16 @@ class TestShapes < Test::Unit::TestCase
           @a = 1
         end
       end
-      # Try to run out of shapes
-      o = Object.new
-      i = 0
-      while RubyVM::Shape.shapes_available > 0
-        o.instance_variable_set(:"@i#{i}", 1)
-        i += 1
-        A.new
-      end
+      RubyVM::Shape.exhaust_shapes
+
+      A.new
     end;
   end
 
   def test_run_out_of_shape_for_class_ivar
     assert_separately([], "#{<<~"begin;"}\n#{<<~'end;'}")
     begin;
-      i = 0
-      while RubyVM::Shape.shapes_available > 0
-        c = Class.new
-        c.instance_variable_set(:"@i#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes
 
       c = Class.new
       c.instance_variable_set(:@a, 1)
@@ -282,12 +261,7 @@ class TestShapes < Test::Unit::TestCase
     begin;
       [].instance_variable_set(:@a, 1)
 
-      i = 0
-      o = Object.new
-      while RubyVM::Shape.shapes_available > 0
-        o.instance_variable_set(:"@i#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes
 
       ary = 10.times.map { [] }
 
@@ -302,12 +276,7 @@ class TestShapes < Test::Unit::TestCase
   def test_run_out_of_shape_for_module_ivar
     assert_separately([], "#{<<~"begin;"}\n#{<<~'end;'}")
     begin;
-      o = Object.new
-      i = 0
-      while RubyVM::Shape.shapes_available > 0
-        o.instance_variable_set(:"@i#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes
 
       module Foo
         @a = 1
@@ -321,12 +290,7 @@ class TestShapes < Test::Unit::TestCase
   def test_run_out_of_shape_for_class_cvar
     assert_separately([], "#{<<~"begin;"}\n#{<<~'end;'}")
     begin;
-      i = 0
-      while RubyVM::Shape.shapes_available > 0
-        c = Class.new
-        c.class_variable_set(:"@@i#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes
 
       c = Class.new
 
@@ -348,13 +312,7 @@ class TestShapes < Test::Unit::TestCase
       class TooComplex < Hash
       end
 
-      # Try to run out of shapes
-      o = Object.new
-      i = 0
-      while RubyVM::Shape.shapes_available > 0
-        o.instance_variable_set(:"@i#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes
 
       tc = TooComplex.new
       tc.instance_variable_set(:@a, 1)
@@ -387,15 +345,10 @@ class TestShapes < Test::Unit::TestCase
       a = Hi.new
 
       # Try to run out of shapes
-      o = Object.new
-      i = 0
-      while RubyVM::Shape.shapes_available > 0
-        o.instance_variable_set(:"@i#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes
 
-      assert_equal 1,a.transition
-      assert_equal 1,a.transition
+      assert_equal 1, a.transition
+      assert_equal 1, a.transition
     end;
   end
 
@@ -409,12 +362,7 @@ class TestShapes < Test::Unit::TestCase
         end
       end
 
-      o = Object.new
-      i = 0
-      while RubyVM::Shape.shapes_available > 0
-        o.instance_variable_set(:"@i#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes
 
       a = A.new
       assert_equal true, a.instance_variable_defined?(:@a)
@@ -424,12 +372,7 @@ class TestShapes < Test::Unit::TestCase
   def test_run_out_of_shape_instance_variable_defined_on_module
     assert_separately([], "#{<<~"begin;"}\n#{<<~'end;'}")
     begin;
-      o = Object.new
-      i = 0
-      while RubyVM::Shape.shapes_available > 0
-        o.instance_variable_set(:"@i#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes
 
       module A
         @a = @b = @c = @d = 1
@@ -445,12 +388,7 @@ class TestShapes < Test::Unit::TestCase
       o = Object.new
       10.times { |i| o.instance_variable_set(:"@a#{i}", i) }
 
-      i = 0
-      a = Object.new
-      while RubyVM::Shape.shapes_available > 2
-        a.instance_variable_set(:"@i#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes
 
       o.remove_instance_variable(:@a0)
       (1...10).each do |i|
@@ -471,12 +409,7 @@ class TestShapes < Test::Unit::TestCase
 
       a = A.new
 
-      o = Object.new
-      i = 0
-      while RubyVM::Shape.shapes_available > 0
-        o.instance_variable_set(:"@i#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes
 
       a.remove_instance_variable(:@b)
       assert_nil a.b
@@ -506,12 +439,7 @@ class TestShapes < Test::Unit::TestCase
 
       a = A.new
 
-      o = Object.new
-      i = 0
-      while RubyVM::Shape.shapes_available > 1
-        o.instance_variable_set(:"@i#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes
 
       a.dup
     end;
@@ -522,12 +450,7 @@ class TestShapes < Test::Unit::TestCase
       o = []
       o.instance_variable_set(:@a, 1)
 
-      i = 0
-      o = Object.new
-      while RubyVM::Shape.shapes_available > 0
-        o.instance_variable_set(:"@i#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes
 
       ary = 1_000_000.times.map { [] }
     begin;
@@ -546,12 +469,7 @@ class TestShapes < Test::Unit::TestCase
     begin;
       class Hi; end
 
-      obj = Hi.new
-      i = 0
-      while RubyVM::Shape.shapes_available > 2
-        obj.instance_variable_set(:"@a#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes(2)
 
       obj = Module.new
       3.times do
@@ -571,12 +489,7 @@ class TestShapes < Test::Unit::TestCase
     begin;
       class Hi; end
 
-      obj = Hi.new
-      i = 0
-      while RubyVM::Shape.shapes_available > 2
-        obj.instance_variable_set(:"@a#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes(2)
 
       obj = Object.new
       i = 0
@@ -748,12 +661,7 @@ class TestShapes < Test::Unit::TestCase
       end
       assert_equal [0, 1, 2, 3, 4], ivars
 
-      o = Object.new
-      i = 0
-      while RubyVM::Shape.shapes_available > 0
-        o.instance_variable_set(:"@i#{i}", 1)
-        i += 1
-      end
+      RubyVM::Shape.exhaust_shapes
 
       object.remove_instance_variable(:@ivar_2)