Simplified the StackFrameList class down to a single frames list again

instead of trying to maintain the real frame list (unwind frames) and an
inline frame list. The information is cheap to produce when we already have
looked up a block and was making stack frame uniquing difficult when trying
to use the previous stack when making the current stack.

We now maintain the previous value object lists for common frames between
a previous and current frames so we will be able to tell when variable values
change.

llvm-svn: 112277