Function try_fuse_group 

pub fn try_fuse_group(
    dims: &[usize],
    strides: &[isize],
) -> Option<(usize, isize)>

Try to fuse a contiguous dimension group into a single (total_size, innermost_stride).

For the group to be fusable, consecutive dimensions must have contiguous strides: stride[i] == stride[i+1] * dim[i+1] for all i.

Returns None if strides are not contiguous within the group.