swift234

CmpXChg Builtin: allow 'weak', return {iNN, i1}

CmpXChg builtins now return (T, Bool) to match the LLVM return value.
Turn the tests back on and check extractvalue / inttoptr instructions.

<rdar://problem/17309776> Update modeling of cmpxchg builtin to handle weak-ness and separate success bit

Swift SVN r23104