The array stride is implementation-dependent if the storage layout is
not standard layout. So this change will use std140 as the layout to
fix the bug.

BUG=767240,angleproject:2255

Change-Id: I21de52ebad6d27783eeade63d6fac81c0842085d
Reviewed-on: https://chromium-review.googlesource.com/861313
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>