Add device extensions to the test framework for supporting custom device (#99960)
Fixes #ISSUE_NUMBER
add a PrivateUse1TestBase in torch/testing/_internal/common_device_type.py for supporting custom device extensions "privateuse1", and add “device_type" parameter in instantiate_device_type_tests function for adding custom device testbase, the default value is None.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/99960
Approved by: https://github.com/albanD, https://github.com/malfet