Update the header guards for clang-modernize.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@189973 91177308-0d34-0410-b5e6-96231b3b80d8
Update the header guards for clang-modernize's unittests.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@189974 91177308-0d34-0410-b5e6-96231b3b80d8