Revert of Make lines a special case in GrShape (patchset #5 id:120001 of https:/...

Revert of Make lines a special case in GrShape (patchset #5 id:120001 of https://codereview.chromium.org/2108523002/ )

Reason for revert:
Assertion failures

Original issue's description:
> Make lines a special case in GrShape
>
> BUG=skia:
> GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2108523002
>
> Committed: https://skia.googlesource.com/skia/+/c62318c748a1907649bd75382c4f4fd10533f2b3

TBR=robertphillips@google.com,egdaniel@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review-Url: https://codereview.chromium.org/2109613003