8165493: SA: Add method in GrowableArray.java to be able to access the 'data' field

Reviewed-by: dholmes, dsamersoff, egahlin

hotspot/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/utilities/GrowableArray.java

@@ -65,4 +65,7 @@ public class GrowableArray<T> extends GenericGrowableArray {
     super(addr);
     virtualConstructor = v;
   }
+  public Address getData() {
+    return dataField.getValue(getAddress());
+  }
 }