Vulkan: drawArrays followed by drawElements bugfix Also add a test in StateChangeTest.cpp to validate the behavior. Bug: angleproject:2458 Change-Id: I58848772c0b4f71aaa3ee187778e49fa08e6800d Reviewed-on: https://chromium-review.googlesource.com/1007320 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Luc Ferron <lucferron@chromium.org> Commit-Queue: Luc Ferron <lucferron@chromium.org>