-Enables more dEQP tests in functional.texture.filtering
-texture.filtering.cube.* tests don't work yet, another CL will be
targeted at fixing that after this one.

Bug: angleproject:2505
Change-Id: Ic634e0deafa54e8e8ebd0efbdae14263ffdbcef0
Reviewed-on: https://chromium-review.googlesource.com/1037183Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Luc Ferron <lucferron@chromium.org>