with COALESCE and JOIN

The server returned to a client the VARBINARY column type
instead of the DATE type for a result of the COALESCE,
IFNULL, IF, CASE, GREATEST or LEAST functions if that result
was filesorted in an anonymous temporary table during
the query execution.

For example:
  SELECT COALESCE(t1.date1, t2.date2) AS result
    FROM t1 JOIN t2 ON t1.id = t2.id ORDER BY result;


To create a column of various date/time types in a
temporary table the create_tmp_field_from_item() function
uses the Item::tmp_table_field_from_field_type() method
call. However, fields of the MYSQL_TYPE_NEWDATE type were
missed there, and the VARBINARY columns were created
by default.
Necessary condition has been added.


mysql-test/r/metadata.result:
  Added test case for bug #39283.
mysql-test/t/metadata.test:
  Added test case for bug #39283.
sql/sql_select.cc:
  Bug #39283: Date returned as VARBINARY to client for queries
              with COALESCE and JOIN
  
  To create a column of various date/time types in a
  temporary table the create_tmp_field_from_item() function
  uses the Item::tmp_table_field_from_field_type() method
  call. However, fields of the MYSQL_TYPE_NEWDATE type were
  missed there, and the VARBINARY columns were created
  by default.
  Necessary condition has been added.