Remove unused argument from WGSL ctor functions.

The parent precedence is not meaningful when assembling ctors, as
the ctor arguments will always have "sequence"-level precedence.

Change-Id: I35543fb106847c2dda700961ac9be25d51531682
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/744662
Commit-Queue: Nicolette Prevost <nicolettep@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Nicolette Prevost <nicolettep@google.com>
2 files changed