Replace arcTo with three functions for it's overloads.

I found this to be about 15% faster on a benchmark designed to stress these functions.

https://github.com/flutter/flutter/issues/61305

Change-Id: I9dc2a8396e54c55464bb71562de0c07c853e829c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/303024
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Nathaniel Nifong <nifong@google.com>
6 files changed