The fix refines the algorithm of generating DROPs for binlog. 
Temp tables with common pseudo_thread_id are clustered into one query. 
Consequently one replication event per pseudo_thread_id is generated.


mysql-test/r/rpl_temporary.result:
  results
mysql-test/t/rpl_temporary.test:
  Creating temp tables associated with a set of pseudo_thread_id values within a connection.
  The aim is to see that slave digest master's binlog consisting of DROP temprorary tables.
sql/sql_base.cc:
  close_temporary_tables is rewritten to generate sequence of DROP temprorary tables with common preudo_thread_id stored in temp table definition.