[Truffle] - Predefined global $~ raises an error if assigned an object not nil or instanceof MatchData
[IR] Bug fixes in AddCallProtocolInstructions pass.

* Cannot support explicit call protocol in IRMetaClassBody yet.
* Fixes sclass_return test when this pass is enabled.
[IR] Fix bug in implementation of PUSH_FRAME instruction

* Fixes a ton of rubyspec errors when AddCallProtocolInstructions
  pass is enabled. One more rubyspec failure to be investigated
  with this pass enabled before this can be considered green
  as well.
Upate RubySpec from Rubinius repo.

RubySpec has been broken into pieces, with core, language, and
command line specs living in the Rubinius repository, and specs
for all stdlibs living in the rubysl projects.

In order to wrap up 2.1 support for JRuby 9k, we need to get the
latest specs, since there are many in our old copy that do not
pass in 2.1 or have behavioral differences.

This means that we will not have the stdlib specs available after
this commit unless we choose to stitch them back together from
rubysl projects. Given the relative coverage of rubysl specs
compared to MRI's tests for the same library, this may not be
worth the effort.
[IR] Bug fix in AliasInstr -- "method_added" callback was missing

* Fixes a rubyspec failure from the recent update.
[Truffle] Temporarily restore separate version of RubySpec for Truffle.

Just until we can get the new specs running in Truffle.
Tag out 4 final IR errors vs AST interp
[Truffle] Move type check of $~ into a separate node.
[Truffle] Ok to compile the special catch for break in a top level block.
[Truffle] Don't pass loop counts to the root method - never going to run it twice.
[Truffle] We need to stop passing counts after the first method that isn't a block.
[Truffle] Give array builders a chance to modify the store after the final element is added.
[Truffle] Convert to the correct array type after the uninitialised builder finishes.
[Truffle] Clear a few things for compilation.
[Truffle] Make some context-global fields final.