pgsql: Fix crash in close_ps() for NaN input coordinates.

Fix crash in close_ps() for NaN input coordinates.

The Assert() here seems unreasonably optimistic.  Andreas Seltenreich
found that it could fail with NaNs in the input geometries, and it
seems likely to me that it might fail in corner cases due to roundoff
error, even for ordinary input values.  As a band-aid, make the function
return SQL NULL instead of crashing.

Report: <87d1md1xji.fsf@credativ.de>

Branch
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REL9_2_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/89b301104a6c5522bb9dc91565ac0e2cb5f4ddb4

Modified Files
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src/backend/utils/adt/geo_ops.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)