add bench for cubicmap

Bug: skia:
Change-Id: Ie88de751e6f889eed02fba1d13e712345256ac72
Reviewed-on: https://skia-review.googlesource.com/147210
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
2 files changed