Vulkan: Minor protected submitCommands() optimization. Bug: angleproject:3965 Change-Id: I52a7597f1dd3bdaf4a221c6b6338caa1577c08f9 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4392876 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Charlie Lao <cclao@google.com> Commit-Queue: Igor Nazarov <i.nazarov@samsung.com>