AArch64/ARM64: put annotation in test

It makes finding already covered tests much easier with "grep -L
arm64".

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208187 91177308-0d34-0410-b5e6-96231b3b80d8
AArch64/ARM64: run test on ARM64 too.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208188 91177308-0d34-0410-b5e6-96231b3b80d8