Improves perf slightly (1-2%) in the Vulkan VBO state change test.

Bug: angleproject:3014
Change-Id: Ia8082b5b3f5e847a6b2775e896893fa8d38c1afd
Reviewed-on: https://chromium-review.googlesource.com/c/1393904
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>