Fix Java tests broken by 559d4068

...a/org/softwareheritage/graph/rpc/NodePropertyBuilder.java

java/src/test/java/org/softwareheritage/graph/GraphTest.java

...rc/test/java/org/softwareheritage/graph/SubgraphTest.java

...t/java/org/softwareheritage/graph/rpc/CountEdgesTest.java

...t/java/org/softwareheritage/graph/rpc/CountNodesTest.java

...a/org/softwareheritage/graph/rpc/FindPathBetweenTest.java

...t/java/org/softwareheritage/graph/rpc/FindPathToTest.java

...test/java/org/softwareheritage/graph/rpc/GetNodeTest.java

...c/test/java/org/softwareheritage/graph/rpc/StatsTest.java

...va/org/softwareheritage/graph/rpc/TraverseLeavesTest.java

...org/softwareheritage/graph/rpc/TraverseNeighborsTest.java

...ava/org/softwareheritage/graph/rpc/TraverseNodesTest.java