Remove DSLFP support.

Ganesh did not adopt DSL FPs, and Graphite is moving to a module-based
solution instead (where we precompile and rehydrate everything once at
startup).

Change-Id: Ie659535739b2d47de654625f65994912c61b0466
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/540301
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
19 files changed