Using the real limits (usually 4096) can cause the uniforms/gl-uniform-arrays
WebGL test to time out.  This limit artificial limit can be lifted once the
test is updated.

BUG=407309

Change-Id: I17a0a963e606800ec4f6f1972c777b597976622f
Reviewed-on: https://chromium-review.googlesource.com/314460Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>