[ARM] GlobalISel: Fix oversight in G_FCMP legalization

We used to forget to erase the original instruction when replacing a
G_FCMP true/false. Fix this bug and make sure the tests check for it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307639 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed