Revert "Create new inset algorithm for spot shadows"

Revert "Create new inset algorithm for spot shadows"

This reverts commit e5f5bf5175e426ebb6aa234f4387831c898f20ad.

Reason for revert: Breaking a bunch of bots. e.g:

https://luci-milo.appspot.com/swarming/task/3519cae0a03c7b10/steps/dm/0/stdout

Original change's description:
> Create new inset algorithm for spot shadows
>
> BUG=skia:
>
> Change-Id: If7c67c2a5b9beea28f86d13362a5156b46394d0e
> Reviewed-on: https://skia-review.googlesource.com/9875
> Commit-Queue: Ravi Mistry <rmistry@google.com>
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Reviewed-by: Robert Phillips <robertphillips@google.com>
>

TBR=jvanverth@google.com,bsalomon@google.com,rmistry@google.com,robertphillips@google.com,msarett@google.com,reviews@skia.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Change-Id: I3d119ff631dbb1a41f873b9c8753d542ec91254e
Reviewed-on: https://skia-review.googlesource.com/10112
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>