Revert "Revert "Redefine the meaning of sample counts in GPU backend.""

Fixes gpu config default samples to be 1 and updates config parsing test accordingly.

This reverts commit c1ce2f7966babaae0deb150f93f1227ee5af9285.

Bug: skia:
Change-Id: I456973b1f52ced85a2011ea10fc49449bfc5846f
Reviewed-on: https://skia-review.googlesource.com/102147
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
88 files changed