This brings the ANGLE_multiview spec in line with WEBGL_multiview.

This also fixes the test so that the timer query extension is
requested when it is being tested.

BUG=angleproject:2062
TEST=angle_end2end_tests

Change-Id: Ibd5c117a5ae2642d26137d9ad44420d6601ba762
Reviewed-on: https://chromium-review.googlesource.com/1143283Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>