It requires GLES 2.0+

This should help keep

src/tests/gl_tests/gles1/TextureParameterTest.cpp:

TextureParameterTest.NegativeEnum

green even if the extension is propagated to the frontend
from the underlying renderer.

Bug: angleproject:3639
Change-Id: I04118e060f38cb774a6897ee6ce035b540a3b60e
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1686822Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Lingfeng Yang <lfy@google.com>