Split channels_last test cases for tensor conversion OpInfos (#67368)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/67368
This PR adds an addition test variant for the tensor conversion
functions (bfloat16, char, long, ...) that tests channels_last. This is
because some backends (mostly just functorch right now) don't have
channels last handling and may want to test that separately from the
more general case of these operations.
Test Plan: - wait for tests
Reviewed By: mruberry
Differential Revision: D31972959
Pulled By: zou3519
fbshipit-source-id: 68fea46908b2cdfeb0607908898bb8f9ef25b264
