Remove deprecated functions

MakeSkDashPathEffect, MakeLinearGradientShader, MakeRadialGradientShader, MakeTwoPointConicalGradientShader,
MakeSkCornerPathEffect, MakeSkDiscretePathEffect, Animation.seek

Change-Id: I07aad20b07bdf45f5c3ee4296a15c2b007570fa1
Docs-Preview: https://skia.org/?cl=278765
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/278765
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Nathaniel Nifong <nifong@google.com>
3 files changed