Vulkan: Fold glClear into draw call when command graph is disabled This sets ContextVk::mRenderPassCommandBuffer properly when glClear get called so that it wonr end up start anotyer render pass during setupDraw call. Bug: angleproject:4395 Change-Id: Id2110719ad4d70b4c410062466d32381fb5e1f88 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2050966 Commit-Queue: Charlie Lao <cclao@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org>