Revert "Revert "moved SkSL ExpressionStatement's data into IRNode""

This reverts commit dd33b3ea9063458be8758e9d0dd564f128107ede.

Change-Id: I348b2b5976966a7451d88bd7f96ce17ce1702b79
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/320826
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
11 files changed