Some users on Linux/Wayland are reporting issues rendering Chrome
unusable when ANGLE exposes GLX_OML_sync_control. This CL adds a new
feature to ANGLE to disable this extension, but for now we leave the
feature off by default, so users can test it via command line flags.

Bug: chromium:1137851
Change-Id: I804ea935fe441c4794b93ee62ca335e78b9e453a
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2468216Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>