This issue was fixed for graphics pipelines (in
UtilsVk::clearFramebuffer), but remained for compute pipelines.  If
UtilsVk issues a dispatch call, it now notifies ContextVk to rebind the
pipeline and descriptor sets.

Bug: angleproject:5529
Change-Id: Ic52f91bdc70d02c065ec2d5e2a3614c11fd62a9f
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2622236
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>