UtilsVk implements some functionality with draw calls.  Of these draw
calls, clear was accidentally contributing to occlusion query results.

Additionally, the copyImage utility creates its own framebuffer and thus
directly creates a render pass, bypassing ContextVk::startRenderPass.
This change also fixes bugs where occlusion query handling assumed
mRenderPassCommandBuffer to be valid and correspond to the started
render pass command buffer, which is not true for the copyImage render
pass.

Bug: angleproject:5042
Change-Id: I19cdbb8fbeabf139791b314a6da265ac5cfd68e5
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2423209
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Charlie Lao <cclao@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>