[Truffle] - Setting the initialize_copy methods as private
[IR] Removed exception region structure state from the CFG.

* The exception regions in a scope were not used anywhere and
  just led to more state that requires maintenance.

* Also removed a few unused imports.
Updated 2.1 grammar with some non-working bits (like imaginary and rational literals)
Remove ParserSupport19
Remove SValue19Node to a single SValueNode
Remove Splat19Node to a single SplatNode
RegexpOptions.setup19 -> setup
[Truffle] - Setting initialize method as private.
Merge pull request #1433 from lucasallan/private-initialize-method

[Truffle] - Defining an 'initialize' or initialize_copy method sets the method's visibility to private
Doh...merging instead of rebasing
Advance lexing enough so i,r,ri suffixes parse but return nil
Allow def foo(**);end to work in parser
rational literal now makes a rational
Hook up complex literal node
Enable syntax tests again, since the file parses now.
[IR] Redid IR for ensure bodies

* JSR-style ensure bodies are removed since this is harder to
  compile into java bytecode using ASM.

* All ensure bodies are now cloned at all sites that they need
  to run (protected body, next, return, break).

  The cloned ensure bodies have different rescue-protection than
  the surrounding code and this required maintaining additional
  information during IR building to make sure that exceptions
  raised in ensure code is protected by the same code as at the
  ensure-code definition site (rather than ensure-code clone site).

* Ensure body cloning made use of previously implemented instruction
  cloning code by adding a new clone mode for slightly different
  semantics than other clone modes.

  TODO: The inliner-info class could use some refactoring and
  cleanup since it now supports 4 different clone modes.

* Eliminated SetReturnAddressInstr and JumpIndirectInstr classes.

* OptimizeTempVarsPass and CFG building is slightly simplified.

* All originally passing ruby specs now pass.
Merge remote-tracking branch 'upstream/master'