Revert "Switch debug builds to use clang."

This reverts commit e190eb50315d9c9c813fd04fbbb9713afabf8c14.

Change-Id: I2089caddbc902a2e90a0d42002b75a2d172abb45
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3306
Reviewed-by: Henry Robinson <henry@cloudera.com>
Tested-by: Nong Li <nong@cloudera.com>
Add missing ALTER TABLE statement in alltypesaggmultifiles table.

The DDL statements for adding the partitions of alltypesaggmultifiles
did not include an ALTER TABLE stmt for one of the partitions, thereby
causing the planner tests to fail when test data were loaded from a
snapshot.

Change-Id: Id4b078cd334d816d6eb8eb15e5856189701a4bca
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3305
Reviewed-by: Dimitris Tsirogiannis <dtsirogiannis@cloudera.com>
Reviewed-by: Lenni Kuff <lskuff@cloudera.com>
Tested-by: jenkins