GrTessellator: missing intersection rewind fix.

Some "missing" intersections (see
https://skia.googlesource.com/skia/+/89042d5f13a56d6b663657aa58f17593123a344e)
cause the active edge list to go out of order. In that case, we need
to rewind the active list, just as we do before edge splitting for
regular intersections.

BUG=860453

Change-Id: I1f7b32157a73b427a4fd94c14c1eb440f26c0743
Reviewed-on: https://skia-review.googlesource.com/141038
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>
2 files changed