This test was updated in r216397, but was failing on Windows due to mixed path...

This test was updated in r216397, but was failing on Windows due to mixed path separators as well as case sensitivity of the "no" in "no such file or directory." Rather than revert this file back to its original form, I've made some incredibly ugly regexes so that it will pass everywhere.

Note, the path this test reports a failure on (for my Windows setup) is: E:\llvm\llvm\tools\clang\test\Frontend/doesnotexist/somename

llvm-svn: 216456