Add recipe for triggering and waiting for G3 compile tasks

NoTry: true
Bug: skia:9021
Change-Id: I20448aebccaa9e408f8942bf05641183aadd9fc8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/216641
Commit-Queue: Ravi Mistry <rmistry@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
4 files changed