pgsql: Add missing COSTS OFF to EXPLAIN commands in rowsecurity.sql.

Add missing COSTS OFF to EXPLAIN commands in rowsecurity.sql.

Commit e5e11c8cc added a bunch of EXPLAIN statements without COSTS OFF
to the regression tests.  This is contrary to project policy since it
results in unnecessary platform dependencies in the output (it's just
luck that we didn't get buildfarm failures from it).  Per gripe from
Mike Wilson.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/654218138b819df66c1b90d39a12ca6a75b9ff65

Modified Files
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src/test/regress/expected/rowsecurity.out |  184 ++++++++++++++---------------
src/test/regress/sql/rowsecurity.sql      |   24 ++--
2 files changed, 104 insertions(+), 104 deletions(-)