Moved the UDF and stored procedure lookup from sql_lex.cc to sql_yacc.yy.
This will improve performance (since we don't have to check for stored
functions in the lexer all the time), and make it possible to implement
db qualified SPs.


mysql-test/r/show_check.result:
  mysql.proc is not used in lex anymore (unless stored functions are really used).
mysql-test/r/status.result:
  mysql.proc is not used in lex anymore (unless stored functions are really used).
sql/sql_lex.cc:
  Moved the UDF and stored procedure lookup to sql_yacc.yy.
sql/sql_yacc.yy:
  Moved the UDF and stored procedure lookup from sql_lex.cc.
  As a result, both stored function and UDF function calls get the
  argument list parsed the same way, so the "AS ..." syntax is
  recognized for both, eventhough it has no meaning for stored
  function.