IMPALA-977: Make AsyncTimeCounter exist in the averaged profile.

Change-Id: Ia7d5afd8aed1577385eba1647766dec84ded842d
Reviewed-on: http://gerrit.ent.cloudera.com:8080/2441
Reviewed-by: Lenni Kuff <lskuff@cloudera.com>
Tested-by: Nong Li <nong@cloudera.com>