[M150] [ganesh] Prevent overflow in StrokeTessellateOp

Original change's description:
> [ganesh] Prevent overflow in StrokeTessellateOp
>
> Bug: b/519168327
> Change-Id: Ic809a5c9c93018bc584b6284ba1b64205485f83b
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/1253636
> Commit-Queue: Thomas Smith <thomsmit@google.com>
> Reviewed-by: Michael Ludwig <michaelludwig@google.com>

(cherry picked from commit dcf3ebf072019fae9f7683e4fdd68b564cc1d579)

Bug: 520437099,b/519168327
Change-Id: Ic809a5c9c93018bc584b6284ba1b64205485f83b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/1256017
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