This can catch unexpected GL errors from ANGLE or the system driver.
Only enable when ASSERTs are enabled to ensure that we get full
performance when profiling.

Helpful to diagnose incorrect perf test rendering. In this case it
helped diagnose that our frame tracing and replay do not correctly
remap uniform locations.

Bug: angleproject:3630
Change-Id: Ifd9f47196381e48f74a810ea0c9f9c0fd7a13a22
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2057352
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tobin Ehlis <tobine@google.com>