clang_tidy: import warn.py from Android

This CL updates our version of |warn.py| to the version from Android.

Please note that this is *not* a bit-for-bit copy of warn.py. It
includes formatting, line splitting, and a few dozen other miscellaneous
lint fixes.

BUG=chromium:960495
TEST=./warn.py on an Android build log. md5sum(result) was equal for
     both the Android copy and our linted/formatted copy.

Change-Id: I69690ac56241bf57cd04b725d493abf8b1b46ecd
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/1600576
Reviewed-by: Caroline Tice <cmtice@chromium.org>
Tested-by: George Burgess <gbiv@chromium.org>
Commit-Queue: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
1 file changed