UNIMPLEMENTED debug spam was causing the tests time time out.  We can mark them
as FAIL again once the dEQP test setup/tear down code doesn't emmit so many
messages.

Implement a couple validation cases for ES 3.1 to greatly reduce the spam.

BUG=angleproject:1647
BUG=angleproject:1442

Change-Id: Ie7b4ac8737a2df1c0ada6ad53154ddf2f37d9c3c
Reviewed-on: https://chromium-review.googlesource.com/415520
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>