ARM: Fix fast-isel copy/paste-o.

ARM: Fix fast-isel copy/paste-o.

Update testcase to be more careful about checking register
values. While regexes are general goodness for these sorts of
testcases, in this example, the registers are constrained by
the calling convention, so we can and should check their
explicit values.

rdar://14779513

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188819 91177308-0d34-0410-b5e6-96231b3b80d8