pgsql: Add a regression test for pgstattuple.

Add a regression test for pgstattuple.

This is mainly to prove that the NaN fix actually works cross-platform.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/bd165757f4e0914efb808927482c46f719adcbc5

Modified Files
--------------
contrib/pgstattuple/.gitignore               |    4 +++
contrib/pgstattuple/Makefile                 |    2 +
contrib/pgstattuple/expected/pgstattuple.out |   38 ++++++++++++++++++++++++++
contrib/pgstattuple/sql/pgstattuple.sql      |   17 +++++++++++
4 files changed, 61 insertions(+), 0 deletions(-)