Added boolean argument to ha_create_table() to ensure that the
Performance Schema can recognize user-defined temporary tables.

ha_create_table() identifies temp tables by the prefix '#sql'
in the table name. User-defined temporary tables do not have
this prefix, so the create info flags are checked for
HA_LEX_CREATE_TMP_TABLE.

The problem is that user-defined temporary tables are truncated
by recreate_temporary_table(), which does not assign the
HA_LEX_CREATE_TMP_TABLE flag in order to avoid a file open
conflict in MyISAM. The new 'is_temp_table' argument is used to
unambiguously identify a temporary table.