Move `contiguous_strides` to `c10/util/strides.h`.
This PR moves `contiguous_strides` implementation from `LinearAlgebraUtils.h` to a broader
scope: `c10/util/strides.h`. This should make it easier to reuse this implementation on
other parts of the codebase.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/76812
Approved by: https://github.com/ezyang
