GitLab

Re-enables or provides disable reasons for all remaining PyLint
disables in the //content/test/gpu pylintrc files and fixes any
resulting warnings.

Bug: 1076144
Change-Id: Ia2732ad9063812e89f00beb6f1d36f989958b624
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2327180Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792961}