moved SkSL Setting data into IRNode and fixed its dehydration/rehydration

Change-Id: Ide129334989890961a46681129672682cf826915
Bug: skia:10819
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/323978
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
11 files changed