ibuf_insert_to_index_page(): Remove bogus code added for delete buffering. In early development of delete buffering, we did allow B-tree pages to become empty as a result of buffered deletes. That caused fundamental problems. The fix was to refuse buffering purge operations unless the page can be guaranteed to be nonempty. Remove an attempt to cope with empty pages when merging inserts.
ibuf_insert_to_index_page(): Remove bogus code added for delete buffering.
In early development of delete buffering, we did allow B-tree pages
to become empty as a result of buffered deletes. That caused fundamental
problems. The fix was to refuse buffering purge operations unless
the page can be guaranteed to be nonempty. Remove an attempt to
cope with empty pages when merging inserts.

flynn1973/mariadb-aix,slanterns/server,davidl-zend/zenddbi,ollie314/server,natsys/mariadb_10.2,davidl-zend/zenddbi,flynn1973/mariadb-aix,ollie314/server,ollie314/server,natsys/mariadb_10.2,davidl-zend/zenddbi,davidl-zend/zenddbi,natsys/mariadb_10.2,ollie314/server,flynn1973/mariadb-aix,flynn1973/mariadb-aix,ollie314/server,davidl-zend/zenddbi,natsys/mariadb_10.2,ollie314/server,ollie314/server,natsys/mariadb_10.2,natsys/mariadb_10.2,davidl-zend/zenddbi,davidl-zend/zenddbi,ollie314/server,flynn1973/mariadb-aix,flynn1973/mariadb-aix,davidl-zend/zenddbi,flynn1973/mariadb-aix,flynn1973/mariadb-aix,natsys/mariadb_10.2,natsys/mariadb_10.2,flynn1973/mariadb-aix,natsys/mariadb_10.2,flynn1973/mariadb-aix,davidl-zend/zenddbi,davidl-zend/zenddbi,natsys/mariadb_10.2,ollie314/server,ollie314/server,flynn1973/mariadb-aix,natsys/mariadb_10.2,davidl-zend/zenddbi,ollie314/server