Fix pr33010, a 2 year old crashing regression

The problem was that we were creating a CMOV64rr <TargetFrameIndex>, <TargetFrameIndex>.  The entire point of a TFI is that address code is not generated, so there's no way to legalize/lower this.  Instead, simply prevent it's creation.

Arguably, we shouldn't be using *Target*FrameIndices in StatepointLowering at all, but that's a much deeper change.  

llvm-svn: 360090