Increase WebGL conformance CQ sharding

Increases the sharding on several CI builders that are mirrored to the
CQ in order to get the total step time under 10 minutes, which is a
project-wide goal this quarter.

Affected CQ builders:
1. android-marshmallow-arm64-rel, currently taking 15 minutes
2. chromeos-amd64-generic-rel, currently taking 13 minutes
3. fuchsia_x64, currently taking 28 minutes

Sharding modifications are made in test_suites.pyl instead of
test_suite_exceptions.pyl to avoid adding any more exceptions, so a
few additional builders have their shards increased as well.

Bug: 1201278
Change-Id: I67821cc424e4cc9ee8df23b8683648362a6d1396
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2844338
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>
Auto-Submit: Brian Sheedy <bsheedy@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#874928}
GitOrigin-RevId: bc984e245f8b925421690db3e00fef7107432bf9
9 files changed