Most UtilsVk functions bind a descriptor set to index 0 (same as driver
uniforms). If that happens to close a render pass, all is well as
starting a new render pass ensures all descriptor sets are rebound.
However, if the render pass is not closed, or if a dispatch call is
issued (which never rebinds descriptor sets if not explicitly
necessary), then the driver uniforms descriptor set may end up never
rebound, causing a validation error (and possible crash or corruption).

This change makes sure that UtilsVk notifies the context when it binds a
descriptor set.  The context then dirties the driver uniforms binding
as appropriate.

Bug: angleproject:4272
Change-Id: Ief20c7884fbe39712f844247489812afc70b30a9
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2027938
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>