[infra] Adjust job priorities. (skcms)

After https://skia-review.googlesource.com/c/buildbot/+/141564,
scheduling will work better if most jobs use the default priority.

Since task priority is now ignored, remove it everywhere.

Bug: skia:8145
Change-Id: I256b4083c4e1ac1cde5a5910792a76e7ad11edc1
Reviewed-on: https://skia-review.googlesource.com/143165
Auto-Submit: Ben Wagner <benjaminwagner@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
2 files changed