Add .clang-format without column limit to subdirectory tests/.

A column limit in the test folder can lead to trouble as the RUN, CHECK,
etc. comments can potentially be broken over multiple lines changing
their meaning. Without column limit, clang-format will simply keep the
test author's line breaks.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@194248 91177308-0d34-0410-b5e6-96231b3b80d8
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: http://llvm.org/svn/llvm-project/cfe/trunk@194249 91177308-0d34-0410-b5e6-96231b3b80d8