reimpl parts of arctTo using doubles to handle shallow angles

Bug: 982968
Change-Id: Ieaf70a406265876655447bd0584717063483808f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/226847
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
4 files changed