Connect DDL offsets in the testing harness to the new ddlTask

This connects these two CLs:

https://skia-review.googlesource.com/c/skia/+/333129 (Update DDL testing harness to support drawing DDL w/ integer offsets)
https://skia-review.googlesource.com/c/skia/+/334422 (Change UnrefDDLTask to just be the DDLTask (take 2))

It still doesn't work though bc it is missing backend support and flags on the tools to enable it.

Change-Id: I51e9c0d41689fce622222201280fb308f1679dcb
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/333579
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
11 files changed