The render pass is now only broken if the indirect buffer was used as
transform feedback.  Any other write to the indirect buffer is
synchronized with `glMemoryBarrier`.

Bug: angleproject:5070
Change-Id: I67868ae9a8f08e1ab186440a3cbdc7439c66808e
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2698996
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>