ProgramGL was unable to handle uniform arrays and improperly set uniform
locations. It now queries the driver for the location of each uniform and
iterates over all array elements.

BUG=angleproject:882

Change-Id: Iffe9d12944b2399f19f4a7823df2f535a430d6e3
Reviewed-on: https://chromium-review.googlesource.com/265724Tested-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>