D3D11: Enable multiview performance tests The patch adds D3D11 as a testable platform to the multiview performance tests. BUG=angleproject:2062 TEST=angle_perftests Change-Id: I2266073860fd53f546ce9a414bc343b582c77f70 Reviewed-on: https://chromium-review.googlesource.com/645849 Reviewed-by: Olli Etuaho <oetuaho@nvidia.com> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Corentin Wallez <cwallez@chromium.org>