FuzzPath -> FuzzNicePath

This CL renames FuzzPath() to FuzzNicePath() to remind us that it's
meant to create paths that a user could reasonably want to create
in good faith, to pass to Skia via its API, etc.

Then, add fuzz_nice_rect(), and have FuzzNicePath() use that to create
its rectangles and use FuzzNiceMatrix() to create its matrices, just
like we already use FuzzNiceRRect() to create rounded rectangles and
FuzzNicePath() itself to create sub-paths.

Using fuzz_nice_rect() should be the fix for the attached bug.
Using FuzzNiceMatrix() is by analogy, more preemptive.

While we're at it, rename BuildPath to FuzzEvilPath, so the contrast
with FuzzNicePath is more clear.

Update the assertions that we create a valid path in FuzzNicePath()
to tell us where things went wrong if they do.

Bug: oss-fuzz:10667, skia:8384
Change-Id: I6d802182a62815cd969c65cf0479609f64b1da55
Reviewed-on: https://skia-review.googlesource.com/156840
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
6 files changed