features: Also check EXT_depth_clamp

This GLES extension has been merged into the OpenGL registry, so it may
now become available.

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
10 jobs for !162 with depth_clamp in 97 minutes and 50 seconds (queued for 33 seconds)
merge request