Remove CQ for unsupported branch chrome/m100

Change-Id: I61d793b745a87bbee708206d28792a2cd310fd07
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/548899
Reviewed-by: Heather Miller <hcm@google.com>
Auto-Submit: Heather Miller <hcm@google.com>
Reviewed-by: Eric Boren <borenet@google.com>