JBR-2645 enable CefBrowser.close(true) in jcef reg tests

(cherry picked from commit 492c217125)

test/jdk/jb/java/jcef/JBCefBrowser.java

@@ -99,7 +99,7 @@ public class JBCefBrowser {
     }
 
     public void dispose() {
-//        myCefBrowser.close(false);
+        myCefBrowser.close(true);
         myCefClient.dispose();
     }
 }