revid:georgi.kodinov@oracle.com-20120309130449-82e3bs5v3et1x0ef
  committer: Georgi Kodinov <Georgi.Kodinov@Oracle.com>
  timestamp: Fri 2012-03-09 15:04:49 +0200
  message:
    Bug #12408412: GROUP_CONCAT + ORDER BY + INPUT/OUTPUT SAME 
    USER VARIABLE = CRASH
    Moved the preparation of the variables that receive the output from 
    SELECT INTO from execution time (JOIN:execute) to compile time 
    (JOIN::prepare). This ensures that if the same variable is used in the
    SELECT part of SELECT INTO it will be properly marked as non-const
    for this query.
    Test case added.
    Used proper fast iterator.

a better fix (much smaller and without regressions) is coming from 5.1