Revert "SkRegion to use pathbuilder"

This reverts commit 72a5d17127ab29d766aff613b74f085ea936ed0a.

Reason for revert: Breaking Chrome roll

Original change's description:
> SkRegion to use pathbuilder
>
> Change-Id: I542bcdb8bb7d4a03a10d23e7adad82aca94ad1ff
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/1016456
> Reviewed-by: Daniel Dilan <danieldilan@google.com>
> Commit-Queue: Mike Reed <mike@reedtribe.org>
> Reviewed-by: Florin Malita <fmalita@google.com>

Change-Id: I0846d44ffe95d5a37d83da2bcb04ba910191ffe3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/1016997
Commit-Queue: Robert Phillips <robertphillips@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
11 files changed