[jit] Split ClassType into a separate header. (#68036)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/68036
In Edge cases we want to separately include class_type.h because in the future we want to stop depending on the rest of the JIT types declared inside jit_type.h
ghstack-source-id: 145818699
Test Plan: no behavior change.
Reviewed By: qihqi, gmagogsfm
Differential Revision: D32264618
fbshipit-source-id: 53dc187772e3dde88ff978b87252c31f3641860b
