moved SkSL Ternary data into IRNode

Change-Id: I70e63aaa73082024c8f0887a941d54cfd12aa2b6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/323883
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
11 files changed