Triangle fan:
- If primitive restart is NOT enabled and there is no active render
  pass, use Compute Shader to generate indices.
- If primitive restart is enabled, use CPU to generate indices.

Line loop:
- If draw non-instanced without primitive restart, generate and
  draw only one additional last segment (fastest).
- If draw instanced, primitive restart is NOT enabled, and there is no
  active render pass, use Compute Shader to generate indices (OK).
- Otherwise, use CPU to generate indices (slowest).

Also Disable OcclusionQueriesTest.ClearNotCounted failure on NVIDIA.

Bug: angleproject:2634
Bug: angleproject:5307
Change-Id: Ia5529825807a964f5fcb2a4af8844778896cd42a
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2435859
Commit-Queue: Le Hoang Quyen <le.hoang.q@gmail.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>