Revert of Fix LCD coverage regression in GrPorterDuffXPFactory (patchset #3 id:40001...

Revert of Fix LCD coverage regression in GrPorterDuffXPFactory (patchset #3 id:40001 of https://codereview.chromium.org/1149883004/)

Reason for revert:
Reverting this fix to revert https://codereview.chromium.org/1124373002

Original issue's description:
> Fix LCD coverage regression in GrPorterDuffXPFactory
>
> Fixes GrPorterDuffXPFactory to not use the blend table when getting
> info about the LCD coverage XP.
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/3e2d59ef36e1b9a63e524cf1b27d5f7bcfb5ff0b

TBR=bsalomon@google.com,egdaniel@google.com,cdalton@nvidia.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1153803005