These were broken by command re-ordering. The first problem was that
the Framebuffer RenderNode was not correctly being flagged as dirty.
This is fixed by keeping a serial instead of a bool to track the
RenderNode's cleanliness. The second issue was that an image layout
transition was being set with incorrect bits. Fix this by using the
correct access mask.

This fixes angle_perftests's Vulkan render test.

Bug: angleproject:2264
Bug: chromium:798866
Change-Id: I268b0f7aeb2c5e22892f6ef59dec62391b30bfb4
Reviewed-on: https://chromium-review.googlesource.com/848539Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>