8202373: Forcing eager initialization of CHM$ReservationNode avoids deoptimization

Reviewed-by: martin, psandoz, dholmes, redestad

src/java.base/share/classes/java/util/concurrent/ConcurrentHashMap.java

@@ -6389,5 +6389,8 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
         // Reduce the risk of rare disastrous classloading in first call to
         // LockSupport.park: https://bugs.openjdk.java.net/browse/JDK-8074773
         Class<?> ensureLoaded = LockSupport.class;
+
+        // Eager class load observed to help JIT during startup
+        ensureLoaded = ReservationNode.class;
     }
 }