Author: Xin Zhang <xzhang@pivotal.io>
Author: Jimmy Yih <jyih@pivotal.io>
Author: Ashwin Agrawal <aagrawal@pivotal.io>

These tests assumed OID == relfilenode. We updated the tests to not assume it
anymore.

These are the same tests queries for column-oriented append-only tables,
as those moved by commit 11a5a807, for row-oriented append-only tables.
There were two additional tests that were never executed for row-oriented
tables though: phantom_reads_update_serializable and
phantom_reads_delete_serializable. I believe that was an oversight in the
original test suite; they are now also executed for row-oriented tables.

We use the UAO templating mechanism, to run the same test files against
row- and column-oriented tables. To make that work, fix a bug in the
templating mechanism pg_regress.c: if the --ao-dir argument was shorter
than 7 characters, the uao directory was not detected correctly.

Change the queries that check tuple counts on a particular segment,
in utility mode, to not print out the exact tuple counts, but a crude
classification of 0, 1, <5 or more tuples. That's less sensitive to how
the tuples are distributed across segments.

The locks_reindex test is moved to the regular regression suite. I rewrote
it to use a more advanced "locktest" view, copied from the
partition_locking test, which doesn't rely on utility mode.

These changes should make the tests work with even larger clusters,
but I've only tested with 1, 2, and 3 nodes.

This new "isolation2" suite uses the same Python helper that TINC used,
to run these special isolation test cases.

TINC is an internal Pivotal test framework which is used for testing Greenplum.
These regression tests are used regularly to validate internal and external
commits. With this commit, nearly all Greenplum test code will be available for
public usage.