[PowerPC]Update Power VSX test cases to also test fast-isel

Update of some of the VSX test cases for Power to check fast-isel codegen as well as the regular codegen.

http://reviews.llvm.org/D6357


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223509 91177308-0d34-0410-b5e6-96231b3b80d8