Breaks dEQP-GLES2.functional.texture.specification.basic_copyteximage2d.2d_alpha BUG=angleproject:1188 This reverts commit 31e60cf2. Change-Id: Icf1fcd984832a813536fe63e385b3cf9f667d66b Reviewed-on: https://chromium-review.googlesource.com/309801Reviewed-by: Corentin Wallez <cwallez@chromium.org> Tested-by: Corentin Wallez <cwallez@chromium.org>
