Vulkan: Minor clean up in CommandProcessor.cpp Minor clean up per the feedback from already merged CLs. Bug: b/255411748 Change-Id: I3d0148700cf79fa597e260e7192d419198f9749f Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4311756 Commit-Queue: Charlie Lao <cclao@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>