Add Linux CPU Coverage Bot

This simply uploads the results of an LLVM coverage to GCS
for later ingestion/display.

Bug: skia:7080
Change-Id: I7dcfa2307a239734a614990aca899ea37129126b
Reviewed-on: https://skia-review.googlesource.com/53880
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
31 files changed