[FastISel][AArch64] Fold the cmp into the select when possible.

This folds the compare emission into the select emission when possible, so we
can directly use the flags and don't have to emit a separate compare.

Related to rdar://problem/18960150.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221847 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed