`gol build`: Duplicate nodes with missing way-node flag

[clarisma]

This happens for duplicate nodes that only belong to foreign ways. The lack of a waynode flag prevents their parent ways from being queried.

Solution:

Validator needs to add a waynode indicator to the special-node Proto-GOL of each duplicate node, so the waynode flag will be set during the node's promotion to feature.

Requires spec change to Proto-GOL.