[Bugfix] Correctly create copiedNodes map when keep_node_ids is false

[rlippolis]

Commit 1c097ca introduced a bug when running the StoryCopy util with keep_node_ids set to false.

In the copyNodes(...) method the MutableLongLongMap copiedNodes is now initialized with a null value when stableNodeIds is false, but it should be the other way around (when using stable node IDs, i.e. keep_node_ids is true, there's no need to keep track of copied node IDs, but when NOT using stable node IDs, the map should be initialized to keep track of the mapping between old and new IDs).

Because the node IDs are not tracked correctly, the correct node IDs cannot be determined when creating the relationships later, resulting in the wrong relationships being created (in case the 'old' node IDs happen to coincidentally match with some new node), or no relationship being created at all (if the old node ID no longer maps to a node in the new graph).

This fix corrects this behaviour. I've also re-added the initialCapacity value of 10_000_000, which was there originally before the above mentioned commit.

[jexp]

Sorry my bad. Thanks a lot!