Additionally, fixes an issue where the read framebuffer was affecting
the render pass desc given to the pipeline.  This fix is included with
this CL as its test depends on glInvalidateFramebuffer.

This issue was revealed by 071d2a44 changing the order in which read and
draw framebuffers were synced.  Previously, read was synced first,
dirtying the pipeline and then draw was synced fixing it.  With the
order reversed, the read framebuffer is the last to changes the
pipeline, leaving it in an invalid state.

Bug: angleproject:3201
Bug: angleproject:3202
Change-Id: Ibebf732a3e3cc081e4865f79dcbaedb467fd9038
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1682468Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>