BUG=angleproject:1589
TEST=dEQP-GLES31.functional.program_uniform.*

Change-Id: I27fffa755fd277ed918746259cac88ab9e349c41
Reviewed-on: https://chromium-review.googlesource.com/412193
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>