Eliminate use of `extract()` in `WP_List_Table::ajax_response()`:

* Extracting `$this->_args` is unnecessary since none of the variables produced are present in the method.
* `total_items` and `total_pages` can be read directly from `$this->_pagination_args`

See #22400.


git-svn-id: https://develop.svn.wordpress.org/trunk@28387 602fd350-edb4-49c9-b593-d223f7449a82
Eliminate use of `extract()` in `WP_Plugin_Install_List_Table::get_table_classes()`. It only needs to read `plural`, no need to extract.

See #22400.


git-svn-id: https://develop.svn.wordpress.org/trunk@28388 602fd350-edb4-49c9-b593-d223f7449a82