pgsql: Fix recently-introduced crash in array_contain_compare().

Fix recently-introduced crash in array_contain_compare().

Silly oversight in commit 1dc5ebc9077ab742079ce5dac9a6664248d42916:
when array2 is an expanded array, it might have array2->xpn.dnulls equal
to NULL, indicating the array is known null-free.  The code wasn't
expecting that, because it formerly always used deconstruct_array() which
always delivers a nulls array.

Per bug #13334 from Regina Obe.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/49ad32d5d99cb4a79bf648c0b7f9eca19b54cf1d

Modified Files
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src/backend/utils/adt/arrayfuncs.c |    2 +-
1 file changed, 1 insertion(+), 1 deletion(-)