The linear command graph prohibits rendering outside the render pass
*after* we begin a renderpass. The prior code would render outside a
render pass (changing image layouts) even after a RenderPass was
started in setupDraw(). The new code changes the image layouts in
ContextVk::syncState so we no longer need to "prepend" image layout
changes after we started a RenderPass. Now we record layout changes
followed by the draw calls or other renderpass ops.

Bug: angleproject:4029
Bug: angleproject:3539
Change-Id: I420858907ac38f995400c1b566c856d966a4e979
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2015940
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Tobin Ehlis <tobine@google.com>