GetInteger64v wasn't introduced until GL 3.2, but some of the enums
for caps that are 64-bit in 3.2 (eg, max uniform block size) were
first introduced as 32-bit values in extensions. This comes up when
trying to use RenderDoc's OpenGL simulator, since it exposes some
relevant extensions and only uses core version 3.1.

BUG=None

Change-Id: Ie4be71b5c8656aae0fe08c270a53f5ef86c99710
Reviewed-on: https://chromium-review.googlesource.com/599030Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>