branches/zip: Fix a bug in the merge sort in fast index creation. Some bug still remains, because innodb-index.test will lose some records from the clustered index after add primary key (a,b(255),c(255)) when row_merge_block_t is reduced to 8192 bytes.
branches/zip: Fix a bug in the merge sort in fast index creation.
Some bug still remains, because innodb-index.test will lose some
records from the clustered index after add primary key (a,b(255),c(255))
when row_merge_block_t is reduced to 8192 bytes.

row_merge(): Add the parameter "half".  Add some Valgrind instrumentation.
Note that either stream can end before the other one.

row_merge_sort(): Calculate "half" for row_merge().


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