pcgv2: Lineage graph seems to ignore future timestamp

[sdorkenw]

Example:

cg = chunkedgraph.ChunkedGraph(graph_id="minnie3_v1")
eval_timestamp = datetime.datetime(2021, 6, 11, 8, 10, 0, 215114, tzinfo=datetime.timezone.utc)

hist = segmenthistory.SegmentHistory(cg, 864691136827214190, timestamp_future=eval_timestamp)
nodes = np.array(list(hist.lineage_graph.nodes()), dtype=np.uint64)

print(np.array(cg.get_node_timestamps(nodes, return_numpy=False)) > eval_timestamp)

Prints

[False False False False False False False False False False False False
 False False False False False False False False False False False False
 False False False False False False False False False False False False
 False False False False False False False False False False False False
 False False False False False False False False False False False False
 False False False False False False False False False False False False
 False False False False False False False False False False False False
 False False False False False False False False False False False False
 False False False False False False False False False False False False
 False False False  True  True  True  True  True  True  True  True  True]