Re-enables 3 tests that were previously failing on Nvidia hardware on
D3D11. The tests seem stable after a trybot driver update.

Bug: angleproject:2896
Change-Id: I17d76a5a67fd57ba7257ef22aa5a1371bf5ed55e
Reviewed-on: https://chromium-review.googlesource.com/c/1308735
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>