Two changes:

1. Treat FMOVD as a copy instruction, to help with coallescing in V9 mode
2. When in V9 mode, insert FMOVD instead of FpMOVD instructions, as we don't
   ever rewrite FpMOVD instructions into FMOVS instructions, thus we just end
   up with commented out copies!
This should fix a bunch of failures in V9 mode on sparc.

llvm-svn: 25961