Remove CQ for unsupported branch chrome/m118

Change-Id: I226ff50bf84a71abc815de36bbc768c7ea77e88b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/804778
Reviewed-by: Heather Miller <hcm@google.com>
Reviewed-by: Eric Boren <borenet@google.com>