turns out that it could cause an infinite loop in some situations. If this code
is triggered and it converts a cleanup into a catchall, but that cleanup was in
already in a cleanup, then the _Unwind_SjLj_Resume could infinite loop. I.e.,
the code doesn't consume the exception object and passes it on to
_Unwind_SjLj_Resume. But _USjLjR expects it to be consumed (since it's landing
at a catchall instead of a cleanup). So it uses the values that are presently
there, which are the values that tell it to jump to the fake landing pad.
<rdar://problem/9508402>

llvm-svn: 132381