[clang-tidy] Fix clang-tidy errors from g3/gsys config Fix the clang-tidy errors found here: https://paste.googleplex.com/6044161211105280 Also add dummy .clang-tidy to prevent errors being thrown from xyz/ directory and auto-generated .pb.h files Google-Bug-Id: 380138738 Change-Id: Iebc449b4d633c603739a4d752a24d77527ebd346 Signed-off-by: David Tang <davtang@google.com>