HANG IN PREPARING WITH 100% CPU USAGE

Infinite loop in the subselect_indexsubquery_engine::exec()
function caused Server hang with 100% CPU usage.

The BLACKHOLE storage engine didn't update handler's
table->status variable after index operations, that
caused an infinite "while(!table->status)" execution.

Index access methods of the BLACKHOLE engine handler
have been updated to set table->status variable to
STATUS_NOT_FOUND or 0 when such a method returns a
HA_ERR_END_OF_FILE error or 0 respectively.