Exception handling is slow in element ReferenceElement creation

Following exception happen for each vertex in OLAP and takes ~10% of execution time.

https://github.com/apache/tinkerpop/blob/master/gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/util/reference/ReferenceElement.java#L48

The exception is always thrown for ComputerGraph.ComputerAdjacentVertex class.

So the check could be added to improve performance. This is 3.3.x issue only, 3.2 has no this problem.