WL#4966: Change default of table_open_cache from 64 to 400

Affects: Server-5.4   —   Status: Complete   —   Priority: Medium

Changed default of table_open_cache from 64 to 400.
In MySQL 5.4.0
In MySQL 5.4.0, change the default of table_open_cache from 64 to 400.

This change is made to provide better “out of box” configuration of default 
values for MySQL operation on up to 16-way x86 servers and 64-way CMT servers
with 4GB or more memory.
Default value of an existing variable changed; no
further LLD required.