`ring_range()`/`tokens_iterator` are more complicated than they need to be. The `include_min` parameter is not used anywhere, and `tokens_iterator` is pimplified without a good reason. Simplify that.
Closes#8805
* github.com:scylladb/scylla:
locator: token_metadata: depimplify tokens_iterator
locator: token_metadata: remove _ring_pos from tokens_iterator_impl
locator: token_metadata: remove tokens_end()
locator: token_metadata: remove `include_min` from tokens_iterator_impl
locator: token_metadata: remove the `include_min` parameter from `ring_range()`
d2157dfea7