Enable tpch queries to run on text to unblock the full data load build.

Some planner tests depend on data being populated in the tpch tmp tables (in text format)
. This change re-enables the tpch query tests to run on text so that they pass.

Change-Id: I4ed09f55e05cb01978cb6f0808c6395552c0f129
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3176
Reviewed-by: Lenni Kuff <lskuff@cloudera.com>
Reviewed-by: Ishaan Joshi <ishaan@cloudera.com>
Tested-by: Ishaan Joshi <ishaan@cloudera.com>
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3177
Disable metric verification for mem-pool.total-bytes.

This is to unblock the builds until IMPALA-1057 is resolved.

Change-Id: I3d2c861737526c33cf48b444c81c429b9abbe829
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3185
Reviewed-by: Lenni Kuff <lskuff@cloudera.com>
Reviewed-by: Ishaan Joshi <ishaan@cloudera.com>
Tested-by: Ishaan Joshi <ishaan@cloudera.com>
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3186
Lower estimated per-host mem cost for sort nodes

Currently, the per-host mem cost for external sort is the same
as that of top-N, i.e. the size of the entire input.
This patch changes the estimated per-host mem cost to be the amount
of memory required for a 2-phase external sort.

Change-Id: I1bf976fa56a3dddf1a6697c75cf82d3a020cdad2
Reviewed-on: http://gerrit.ent.cloudera.com:8080/3018
Reviewed-by: Marcel Kornacker <marcel@cloudera.com>
Tested-by: jenkins