IMPALA-1240: add back spilling sort now that sorter is not flaky
IMPALA-1240: add back spilling sort now that sorter is not flaky

This test coverage was removed because of flakiness.
Instead of mem_limit, use max_block_mgr_memory, which is more
deterministic since it isn't affected by scanner memory usage.
Now that the sorter is more stable, this test should reliably
succeed.

Change-Id: I88056db2eac3fa91bef85284a516be303f25333d
Reviewed-on: http://gerrit.cloudera.org:8080/3795
Reviewed-by: Tim Armstrong <2f8e34250f03a653da3dc27f7ec203eafdde80fc@cloudera.com>
Tested-by: Internal Jenkins

michaelhkw/incubator-impala,michaelhkw/incubator-impala,michaelhkw/incubator-impala,cloudera/Impala,cloudera/Impala,cloudera/Impala,cloudera/Impala,michaelhkw/incubator-impala,cloudera/Impala,cloudera/Impala,michaelhkw/incubator-impala,michaelhkw/incubator-impala,michaelhkw/incubator-impala,cloudera/Impala