Add Metal compile bot to CQ

Bug: skia:
Change-Id: Ifaf94d100bf4213ee405086f72313884ef003486
Reviewed-on: https://skia-review.googlesource.com/60340
Reviewed-by: Greg Daniel <egdaniel@google.com>
Reviewed-by: Ravi Mistry <rmistry@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
1 file changed