[clang] Disable a few formatting options for test/
Hopefully this will make the bot a little less noisy. Rationale for each:
AlignTrailingComments: We don't want to force-align the various expected-error
CommentPragmas: Tell clang-format to leave the "// CHECK:" and the
"// expected-" alone.
AlwaysBreakTemplateDeclarations: Templates in tests often have no break between
the template-head and the declaration.
Differential Revision: https://reviews.llvm.org/D83901