On our Renderer test, we would be overly restrictive in the forms
of Renderer string we would accept for WARP. On this machine, it
returns a different string than the one we had in the test. Expand
the test to accept both.

BUG=angle:769

Change-Id: If27644d32d6d7d0eff77ff9cca81faee3b2be4e1
Reviewed-on: https://chromium-review.googlesource.com/221066Reviewed-by: Brandon Jones <bajones@chromium.org>
Reviewed-by: Shannon Woods <shannonwoods@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>