Revert "When waiting on client provided semaphores, only block fragment stage work."

This reverts commit fd780675ee1798738d6369fc20ee0fdfc6ddac8d.

Reason for revert: speculative revert to see if this caused flakiness in chrome tests. https://bugs.chromium.org/p/chromium/issues/detail?id=1492267#c1

Original change's description:
> When waiting on client provided semaphores, only block fragment stage work.
>
> All current clients that use these wait APIs really just want Skia to
> block on fragment work. In practice there isn't a current way for a
> client provided gpu resource to even be used outside of a fragment
> shader in Skia. This change allows the driver to begin processing vertex
> work while waiting on the semaphore to signal.
>
> Change-Id: I7733a7316bcb67025683ea234a34f0cbd12a0694
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/765317
> Reviewed-by: Nicolette Prevost <nicolettep@google.com>
> Commit-Queue: Nicolette Prevost <nicolettep@google.com>
> Auto-Submit: Greg Daniel <egdaniel@google.com>

Change-Id: If09a0ae6ac8bb8bcf41e396faf24e78f5618199c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/766476
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Nicolette Prevost <nicolettep@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
Auto-Submit: Greg Daniel <egdaniel@google.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
7 files changed