ARM: Constrain regclass for TSTri instruction.

Get the register class right for the TST instruction. This keeps the
machine verifier happy, enabling us to turn it on for another test.

rdar://12594152

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189274 91177308-0d34-0410-b5e6-96231b3b80d8
ARM: Enable machine verifier for a few more tests.

Now that fast-isel is in better shape, we can enable the machine
verifier for these tests, too.

rdar://12594152

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189275 91177308-0d34-0410-b5e6-96231b3b80d8