Remove dead no-sorting GrDrawingManager code paths

This simplifies our world a little bit.

Bug: skia:10877
Change-Id: I2fb27cd53e9fda0f279c046f6eaa50fd02774e72
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/332604
Commit-Queue: Robert Phillips <robertphillips@google.com>
Auto-Submit: Adlai Holler <adlai@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
6 files changed