Make shadow_utils GM use its own SkResourceCache

This should stabilize the replay testing on the bots.

Change-Id: I89e3e308000743da6e1a765751103cffabc7e4ba
Reviewed-on: https://skia-review.googlesource.com/8902
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
3 files changed