[Stackmap] Specify the triple and cpu to fix the unit test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196339 91177308-0d34-0410-b5e6-96231b3b80d8
Add -mcpu=core2 to all llc invocations in this test.

Should fix the atom buildbot.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196340 91177308-0d34-0410-b5e6-96231b3b80d8