Allow LocalNode to be extended for customisation (#11718)

LocalNode currently has a private constructor 
Which prevents it from being extended for customisation.
Exposing the constructor for classes extending it.

Author: krmahadevan

java/src/org/openqa/selenium/grid/node/local/LocalNode.java

@@ -134,7 +134,7 @@ public class LocalNode extends Node {
   private final AtomicInteger pendingSessions = new AtomicInteger();
   private final AtomicInteger sessionCount = new AtomicInteger();
 
-  private LocalNode(
+  protected LocalNode(
     Tracer tracer,
     EventBus bus,
     URI uri,