[clang tools] Don't print edit lines when no replacements exist

This change modifies clang tools to not print '==== BEGIN EDITS ===='
and '==== END EDITS ====' in case no replacements exist.

Change-Id: Icdd2b3df5f10ca37c73c9ffc63cb0830192e1ec7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2124753
Commit-Queue: Jan Wilken Dörrie <jdoerrie@chromium.org>
Auto-Submit: Jan Wilken Dörrie <jdoerrie@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#754354}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 9184fd68b5126c828a37641a7e97129c97c81be9
5 files changed