[nobuildbot] Mac bots

BUG=skia:

Change-Id: I089a21941b65d4bb53e803c4d5081b26bda30f14
Reviewed-on: https://skia-review.googlesource.com/5210
Reviewed-by: Ben Wagner <benjaminwagner@google.com>
tree: f7fca5106ed573a8477546ddca0ddc51cacb6b2a
  1. recipe_modules/
  2. recipes.py
  3. recipes/