pgsql: Jsonb comparison bug fixes.

Jsonb comparison bug fixes.

Fix an over-zealous assertion, which didn't take into account that sometimes
a scalar element can be compared against an array/object element.

Avoid comparing possibly-uninitialized local variables when end-of-array or
end-of-object is reached. Also fix and enhance comments a bit.

Peter Geoghegan, per reports by Pavel Stehule and me.

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/b3e5cfd5f979054e31d60adafd9e75bf9c38549a

Modified Files
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src/backend/utils/adt/jsonb_util.c | 63 ++++++++++++++++++++++--------------
1 file changed, 38 insertions(+), 25 deletions(-)