Add gradual typing constraint definitions (#79912)
Differential Revision: [D37315020](https://our.internmc.facebook.com/intern/diff/D37315020)
Add high-level gradual type constraint definitions. Those definitions will be used by the constraint generator. The generator will generate high-level constraints for FX graphs which will then be transformed to constraints that are understood by Z3
Pull Request resolved: https://github.com/pytorch/pytorch/pull/79912
Approved by: https://github.com/anijain2305, https://github.com/jamesr66a
