[ROCm] restore jit tests (#40447)
Summary:
Remove `skipIfRocm` from most jit tests and enable `RUN_CUDA_HALF` tests for ROCm.
These changes passed more than three rounds of CI testing against the ROCm CI.
CC ezyang xw285cornell sunway513
Pull Request resolved: https://github.com/pytorch/pytorch/pull/40447
Differential Revision: D22190711
Pulled By: xw285cornell
fbshipit-source-id: bac44825a2675d247b3abe2ec2f80420a95348a3
