Fix query plan tests on neo4j 3.5
Fix query plan tests on neo4j 3.5

Operator type names have changed. This commit makes the assertions
more generic.

neo4j/neo4j-javascript-driver,neo4j/neo4j-javascript-driver,neo4j/neo4j-javascript-driver,neo4j/neo4j-javascript-driver,neo4j/neo4j-javascript-driver