Remove fragment-processor stack from DSL ThreadContext.

This was no longer referenced anywhere.

Change-Id: I479c70e528e48c8c1a8945230739ecf0a87c3f9d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/541746
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
2 files changed