Improve the missing ASM parser test for MS-style assembly

It's better to test clang-check rather than the internal c-index-test utility.

Also adds a target so we can remove the XFAILs.

Thanks to Richard Barton for spotting the test failure on ARM.

Test originally from r193685.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@194249 91177308-0d34-0410-b5e6-96231b3b80d8