[Truffle] - Initial support to ByteList on RubyString.

This is the first step to make the encoding works with RubyString.
Add missing temporarylocalvariable visitor on encode of persist
trivial remove unused import
Change OperandTypes to be distinct between boxed and unboxed values.  Added rest of changes to IRVisitor so persistence encoding is working again (reading still broken)
[IR] Implement GVarAliasInstr.
[IR] Implement Match, Match2, and Match3 instructions.
[IR] Implement OptArgMultipleAsgnInstr...I think.
Remove vestiges of GSoC persistence
Remove defunct NotNode from AST and consumers.
Remove defunct NotInstr.
Merge branch 'master' of jruby.org:jruby