private static IntUnaryOperator skipCandidatePorts(int n) {
    return port -> {
      int nextPort = port + n;
      if (nextPort <= AVAILABLE_PORTS_UPPER_BOUND) {
        return nextPort;
      }
      return AVAILABLE_PORTS_LOWER_BOUND;
    };
  }
Assign this JVM's next candidate port based on the given index. If each JVM in the same test
calls this function with a small, distinct number, the algorithm:
<ul>
<li>Separates the JVMs' next candidate ports reasonably well</li>
<li>Allows adding JVMs without needing to know the total number of JVMs ahead of time</li>
</ul>

@param jvmIndex a small number different from that of any other JVM running in this test
geode-junit/src/main/java/org/apache/geode/internal/AvailablePortHelper.java