Add label filter after multi-labeled extend

[andyfengHKU]

Consider query MATCH (a:person)-[:mixed]->(b:person)

Our storage partition list based on bound node label, rel label and direction. So given (:person, :mixed, FWD), we will fetch an adjList that points to both person and organization. We need to apply an additional label filter after extend to make sure only person label will be processed further.

Note this will not cause a bug because later HashJoin will only join on person label. But this should be an optimization.

[andyfengHKU]

This is no longer the case because we now only allow one src/dst node per rel. Pruning is done in PR #1329