Ignore special ARM allocation hints for unexpected register classes.

Add an assertion to linear scan to prevent it from allocating registers outside
the register class.

<rdar://problem/9183021>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128254 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed