ES31: Sync dirty objects for compute shader BUG=angleproject:2395 TEST=angle_end2end_tests Change-Id: Ife833a6573c49fc453c120ebc66765064d807b16 Reviewed-on: https://chromium-review.googlesource.com/954991 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>