Added unsigned types and type query functions to DSL

Change-Id: I721825d1a38e9f6846b94f84d14cb8c85b7a7519
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/403601
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
5 files changed