Incorrect handling of multiple keys in the same chunk when inserting to join hash table.

[andyfengHKU]

The following query will output incorrect result

MATCH (a:person)-[e1:knows]->(b:person), (a)-[e2:meets]->(b) WHERE a.age > 0 RETURN a.fName, b.fName

This is because e2 is a column extend and thus both keys "a" and "b" are in the same data chunk. However, our join hash table seems to unable to differentiate whether "a" and "b" are in the same chunk or not and thus always taking a Cartesian product.