Restrict parquet many cols test to one test dimension.

Change-Id: Ib7e1a63a9981fc646899b627748b523119d9a5d4
Reviewed-on: http://gerrit.ent.cloudera.com:8080/1928
Reviewed-by: Lenni Kuff <lskuff@cloudera.com>
Tested-by: Nong Li <nong@cloudera.com>
(cherry picked from commit 2ead746f0e697276e7753c735befbd1a14feba6d)
Reviewed-on: http://gerrit.ent.cloudera.com:8080/1934
Reviewed-by: Nong Li <nong@cloudera.com>