Removed the hack that uses "frame variable" to
evaluate expressions.  The expression parser and
IR interpreter are now fully capable of evaluating
expressions with as much (or better) fidelity.

<rdar://problem/12879364>


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@172293 91177308-0d34-0410-b5e6-96231b3b80d8