Clang-format and whitespace cleanup of source code

This patch contains the clang-format and cleanup of the entire code base. Some
of clang-formats changes made the code look worse in places. A best effort was
made to resolve the bulk of these problems, but many remain. Most of the
problems were mangling line-breaks and tabbing of comments.

Patch by Terry Wilmarth

Differential Revision: https://reviews.llvm.org/D32659


git-svn-id: https://llvm.org/svn/llvm-project/openmp/trunk@302929 91177308-0d34-0410-b5e6-96231b3b80d8