Mark some nullable fields as nullable
Add comments where necessary
Adjust boolean logic to unconditionally run for loop, as its enclosing if statement will always be true
Remove logger that we don't really ever use

When we get an edge from the edge cache make sure to update its transitive exlcudes.
Since the edge is not attached at that point, also make sure to always recompute
a node's transitive excludes when an edge is added to it.

This can potentially open up optimizations in the future where we compute the node
exclusions eagerly when the edge is added to it, and only if the transitive excludes
change do we enqueue the node.

Add missing issue annotation to regression test
Fix test name
Fix javadoc wording
Update confusing/out-of-date comment