Represent scalar-cast constructors with ConstructorScalarCast.

Change-Id: Iff8477f3797c83059c823ca9287493b7f30db71b
Bug: skia:11032
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/392438
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
21 files changed