[CUBRIDMAN-177] replace the information which is printed in "show trace" from aggregate function optimization

[beyondykk9]

http://jira.cubrid.org/browse/CUBRIDMAN-177

The trace information is printed from "show trace" command, however, the aggregate optimzation-related information is not printed.

The new TRACE message is as follows:

   Trace Statistics:
      SELECT (time: 0, fetch: 16, ioread: 0)
         SCAN (table: agl_tbl), (noscan time: 0, fetch: 0, ioread: 0, readrows: 0, rows: 0, agl: pk_agl_tbl_id)