Implement CLASS NODE locations

The following Location information has been added This is the information required for parse.y to be a universal parser:

```
❯ ruby --parser=prism --dump=parsetree -e "class A < B; end"
@ ProgramNode (location: (1,0)-(1,16))
+-- locals: []
+-- statements:
    @ StatementsNode (location: (1,0)-(1,16))
    +-- body: (length: 1)
        +-- @ ClassNode (location: (1,0)-(1,16))
            +-- locals: []
            +-- class_keyword_loc: (1,0)-(1,5) = "class"
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
            +-- constant_path:
            |   @ ConstantReadNode (location: (1,6)-(1,7))
            |   +-- name: :A
            +-- inheritance_operator_loc: (1,8)-(1,9) = "<"
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
            +-- superclass:
            |   @ ConstantReadNode (location: (1,10)-(1,11))
            |   +-- name: :B
            +-- body: nil
            +-- end_keyword_loc: (1,13)-(1,16) = "end"
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
            +-- name: :A
```

1 files changed, 8 insertions, 0 deletions

diff --git a/test/ruby/test_ast.rb b/test/ruby/test_ast.rb
index 86676ac577..887dbb6ecf 100644
--- a/test/ruby/test_ast.rb
+++ b/test/ruby/test_ast.rb
@@ -1376,6 +1376,14 @@ dummy
       assert_locations(node.children[-1].locations, [[1, 0, 1, 17], [1, 0, 1, 4], [1, 14, 1, 17]])
     end
 
+    def test_class_locations
+      node = ast_parse("class A end")
+      assert_locations(node.children[-1].locations, [[1, 0, 1, 11], [1, 0, 1, 5], nil, [1, 8, 1, 11]])
+
+      node = ast_parse("class A < B; end")
+      assert_locations(node.children[-1].locations, [[1, 0, 1, 16], [1, 0, 1, 5], [1, 8, 1, 9], [1, 13, 1, 16]])
+    end
+
     def test_dot2_locations
       node = ast_parse("1..2")
       assert_locations(node.children[-1].locations, [[1, 0, 1, 4], [1, 1, 1, 3]])