[WinEH] Update PHIs of CATCHRET successors

The TailDuplication machine pass ran across a malformed CFG: a PHI node
referred it's predecessor's predecessor instead of it's predecessor.
This occurred because we split the edge in X86ISelLowering when we
processed the CATCHRET but forgot to do something about the PHI nodes.

This fixes PR25444.

llvm-svn: 252413