[ARM] Rejig vmax tests a bit

They rely on global fast-math options, but soon ISel will rely only on fast-math flags on the instructions themselves. Rip the fast checks out into their own file so we can mark their instructions as fast.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244914 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed