Avoid reading unused lvars in Primitive.cexpr

	Previously on builds with optimizations disabled, this could result in
	an out of bounds read. When we had all of:
	* built with -O0
	* Leaf builtin
	* Primitive.mandatory_only
	* "no args builtin", called by vm_call_single_noarg_inline_builti
	* The stack is escaped to the heap via binding or a proc

	This is because mk_builtin_loader generated reads for all locals
	regardless of whether they were used and in the case we generated a
	mandatory_only iseq that would include more variables than were actually
	available.

	On optimized builds, the invalid accesses would be optimized away, and
	this also was often unnoticed as the invalid access would just hit
	another part of the stack unless it had been escaped to the heap.

	The fix here is imperfect, as this could have false positives, but since
	Primitive.cexpr! is only available within the cruby codebase itself
	that's probably fine as a proper fix would be much more challenging (the
	only false positives we found were in rjit.rb).

	Fixes [Bug #20178]

	Co-authored-by: Adam Hess <HParker@github.com>
	---
	 bootstraptest/test_method.rb | 9 +++++++++
	 tool/mk_builtin_loader.rb    | 6 ++++++
	 2 files changed, 15 insertions(+)

* `-j` option for concurrent test with threads
  * `-jN` uses N threads
  * `-j` uses nproc/2 threads
* Introduce `BT` struct to manage configurations
* Introduce `Assertion` to manage all assertions
* Remove all toplevel instance variables
* Show elapsed seconds at last

```
$ time make btest
...
real    0m37.319s
user    0m26.221s
sys     0m16.534s

$ time make btest TESTOPTS=-j
...
real    0m11.812s
user    0m36.667s
sys     0m21.872s
```

* bootstraptest/test_method.rb: relax error message format.
* test/ruby/test_arity.rb (err_mess): ditto.
  [Feature #9025], [ruby-core:71178] [Bug #11617]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52265 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

  obsolete.
  Please check btest, too.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50964 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

* ext/socket/init.c, ext/socket/socket.c, ext/socket/tcpsocket.c
  ext/socket/udpsocket.c, gc.c, object.c, re.c, safe.c: removed code
  for $SAFE=3
* bootstraptest/test_method.rb, test/erb/test_erb.rb, test/ruby/test_dir.rb
  test/ruby/test_file.rb, test/ruby/test_method.rb, test/ruby/test_regexp.rb
  test/ruby/test_thread.rb: remove tests for $SAFE=3

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50932 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44601 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

  remove tests for $SAFE=4.

* lib/pp.rb: use taint instead of untrust to avoid warnings when
  $VERBOSE is set to true.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41269 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

  ci->argc and ci->blockptr before and after method invocations
  because these method dispatches override call_info.
* bootstraptest/test_method.rb: add tests for this fix.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37641 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

  this method call needs splat argument because cahced functions
  (vm_call_attrset, vm_call_ivar, vm_call_cfunc_fast_(unary|binary))
  do not check an arity.
* bootstraptest/test_method.rb: add a test to check an above issue.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37199 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@32146 b2dd03c8-39d4-4d8f-98ff-823fe69b080e