added 'in_rows' column value for 'describe extended' for the case 
when 'describe' handles I_S table


mysql-test/r/information_schema.result:
  test result
mysql-test/t/information_schema.test:
  test case
sql/sql_select.cc:
  added 'in_rows' column value for 'describe extended' for the case 
  when 'describe' handles I_S table