branches/zip: buf_page_get_gen(): Ignore "guess" if it does not point to buf_pool->chunks[]->blocks[].
branches/zip: buf_page_get_gen(): Ignore "guess" if it does not point to
buf_pool->chunks[]->blocks[].

buf_block_is_uncompressed(): New function, to detect if a block points to
buf_pool->chunks[]->blocks[].

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