Add more tests for PolyUtils

* Add fuzzer
* Add bench tests
* Add additional unit test
* Fix some bugs these exposed.

Bug: skia:
Change-Id: I6c587c92cb6cff32ab8300020b78f9f247d2bf64
Reviewed-on: https://skia-review.googlesource.com/139169
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index f10d232..11b1943 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1749,6 +1749,7 @@
       "fuzz/FuzzParsePath.cpp",
       "fuzz/FuzzPathMeasure.cpp",
       "fuzz/FuzzPathop.cpp",
+      "fuzz/FuzzPolyUtils.cpp",
       "fuzz/FuzzRegionOp.cpp",
       "fuzz/fuzz.cpp",
       "fuzz/oss_fuzz/FuzzAnimatedImage.cpp",