[Reland] Fix NVPR assert for equivalent ovals

[Reland] Fix NVPR assert for equivalent ovals

For oval paths, GrPath ignores the point order and only uses the bounds
when building its key.  This is problematic because

1) point order is important when dashing
2) GrStencilAndCoverPathRenderer asserts that the lookup SkPath is equal
   to the cached SkPath - which is not the case for ovals with different
   directions/different point order.

With this CL we no longer use the reduced oval key when dashing, and
instead fall through to the more general path cases.  The assert is
adjusted to accommodate "equivalent" ovals (when not dashing).

Also re-enabled & updated the GpuDrawPath unit test (disabled in
https://codereview.chromium.org/1456463003/, presumably due to the use
of uninitialized SkRects).

R=bsalomon@google.com,robertphillips@google.com,cdalton@nvidia.com

Review URL: https://codereview.chromium.org/1457073002