[clang-format] NFC - clang-format the FormatTests
Ensure the clang-format unit tests are themselves clang-formatted
Having areas of the llvm code which are clang-format clean, give us more areas to run new clang-format binaries on ensuring we haven't broken anything.
It seems to me we SHOULD have this clang-formatted at a minimum, otherwise how can we expect others to use clang-format if we "don't eat our own dogfood", also if the tests are dependent on the formatting of the code then that would also be bad!
Reviewed By: sammccall
Tags: #clang, #clang-format
Differential Revision: https://reviews.llvm.org/D79204