remove unused clipRect for distance field

In the call insertSubRunOpsIntoTarget, the clipRect is always empty
for the distance field case.

Change-Id: Ib17eaae37a153c5b6aa473b2bf31d8b6c985e78f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/301257
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
3 files changed