Restore test from r211844 skipping '.file' directives

At least this answers the question of whether .bc/.ll input processed by the
frontend produces identical output to the original compilation.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211853 91177308-0d34-0410-b5e6-96231b3b80d8
Account for differences in grep implementations

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211856 91177308-0d34-0410-b5e6-96231b3b80d8
[OPENMP] Added several test cases in nesting of OpenMP regions test after review from Samuel F Antao.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211857 91177308-0d34-0410-b5e6-96231b3b80d8