Various OpInfo architecture improvements
This PR makes the following improvements:
- moves the custom skip list for test_normalize_operator_exhaustive in test_fx_experimental to use the typical OpInfo skip architecture. The skips were updated to xfails, and that identified some operators which were no longer failing the test
- redundant tests with OpInfo-based testing in test_jit.py were removed
- test_dtypes was improved so its error messages are clear and it makes test_nondifferentiable redundant; the latter test has been removed
- OpInfo.supports_complex_autograd() is removed in favor of a more accurate and general test for whether the particular dtype is in the backward dtypes of the operator
- gradchecks have been improved to verify that an operator doesn't support grad if it claims not to
- gradchecks have been improved to test the gradient of all input tensors that require gradient
- the concept of "default test dtypes" has been removed
- excessive and mostly redundant out testing for elementwise unary operators has been removed
- metadata for whether an op supports nuanced "safe casting" to out behavior has been removed from OpInfos
- numerous skips have been converted to xfails
- numerous OpInfos have had their metadata fixed based on the new checks
- jit-specific utilities in common_methods_invocations.py have been moved to jit_programming_utils.py
Pull Request resolved: https://github.com/pytorch/pytorch/pull/75951
Approved by: https://github.com/ngimel
