[inductor] Revert channels-last support (#87588)
We witnessed slow compilation times last week. Earlier, I thought it was due to parallel compilation. But, after git bisect, I found the source of extra time to be my PR - https://github.com/pytorch/pytorch/pull/87049
For 1x1 kernel, the current striding check incorrectly declares channels-first 1x1 convs to channels last. I am not sure why it caused so much compilation time jump. Or why it did not fail? There was no change in performance speedup. cc @jansel @lezcano @fdrocha @mlazos @soumith @voznesenskym @yanboliang @penguinwu to identify what could be source of this compilation time increase, so that we can manually check that part of the stack.
With this `res2next50` compilation time went back to 96 seconds (which was raised to 900 seconds with my earlier PR) for single thread. And parallel-compilation brings it down to ~30 seconds.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/87588
Approved by: https://github.com/soumith, https://github.com/jansel, https://github.com/ngimel
