[infra] Add ccache for mac default builds.

Also add pre and post build ccache stats reporting to provide insight for cache size, hit rate, etc.

Bug: skia:9887
Change-Id: I3786fb661ef9f14bdc9fcc7cbcecd1f1a588479f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/269370
Commit-Queue: Weston Tracey <westont@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
30 files changed