Works around performance regressions when index and vertex buffer bind flags are used on the same buffer.

Change-Id: I28bc0d3147c6bd70cec507f20e41d97ec4cc45a5
Reviewed-on: https://chromium-review.googlesource.com/181911Tested-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shannon Woods <shannonwoods@chromium.org>