Fix how strides is set on Py_buffer object when the array is C-contiguous

This is a possible fix for #5085.

A complete solution would probably convert the strides array from something containing -1's into the equivalent without them, but I don't know all the corner cases involved with that.
Thanks for looking into it. This is good for C-contiguous arrays, could you add an `else if` for fortran arrays, just to be as complete as possible? You will certainly have to fixt the strides by hand then I think.

The memory management is fine with `view->strides` being `NULL` because `info` is used for freeing that memory?