7017486: Need synchronized access when flushing the LDAP request queue

Reviewed-by: alanb

src/share/classes/com/sun/jndi/ldap/Connection.java

@@ -656,16 +656,19 @@ public final class Connection implements Runnable {
                 }
                 nparent = notifyParent;
             }
-        }
             if (nparent) {
                 LdapRequest ldr = pendingRequests;
                 while (ldr != null) {
+
+                    synchronized (ldr) {
                         ldr.notify();
                         ldr = ldr.next;
                     }
+                }
                 parent.processConnectionClosure();
             }
         }
+    }
 
 
     // Assume everything is "quiet"