hone down the SK_FORCE_RASTER_PIPELINE_BLITTER test bot

We only are really interested in 8888 GMs for this bot.
Unit tests and other configs don't need to run.

CQ_INCLUDE_TRYBOTS=skia.primary:Test-Ubuntu-Clang-GCE-CPU-AVX2-x86_64-Release-SK_FORCE_RASTER_PIPELINE_BLITTER

Change-Id: Iec4e5566cc27e82fea0d5832c514a5141ff80cfa
Reviewed-on: https://skia-review.googlesource.com/16499
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Eric Boren <borenet@google.com>
2 files changed