Fix uniform locations in ProgramGL. 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/265724 Tested-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Kenneth Russell <kbr@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>