This implements one of the two remaining C functions:
numba_list_delete_slice at the C, compiler, and interpreter level. Tests
are included. The implementation was copied from the relevant parts of
the cpython source code in `list_ass_subscript` but doesn't exactly
mirror any specific function. This should also enable acceleration of
some other bits of the code.

When using setitem with a slice and an item that is smaller than the
slice, we need to remove items. Until now, this was done with pop, which
actually incurred a memory move of the tail of the list for every item
being removed. Now that we can mass delete items in the list with `del`
and slices, we used that functionality instead.

`_list_get_data` was moved and renamed to `_container_get_data`, this
bug stems from a failed rebase.