[jit][edge] Create convinience wrapper for dynamic type construcytors. (#71457)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/71457
Today DynamicType is hard to be created because we have separare APIs for different types. In this diff we introduce an easier API to create types like the following:
```
#include <ATen/core/type_factory.h>
auto type = dynT<ListType>(dynT<TensorType>()); // etc...
```
ghstack-source-id: 147211236
Test Plan: CI
Reviewed By: iseeyuan
Differential Revision: D33647746
fbshipit-source-id: c850cf31ae781244eac805906a2fc110ef065a70
(cherry picked from commit 8cfd51d75f010ca6f7f98b7e8ef807ead4d5f8f3)
