Fixes #7514 - Adding InheritedListeners to already-started components…

… can cause IllegalStateException

Removed the unnecessary check-and-throw statements from SelectorManager.

Signed-off-by: Simone Bordet <simone.bordet@gmail.com>

jetty-io/src/main/java/org/eclipse/jetty/io/SelectorManager.java

@@ -396,8 +396,6 @@ protected void connectionFailed(SelectableChannel channel, Throwable ex, Object
     @Override
     public boolean addEventListener(EventListener listener)
     {
-        if (isRunning())
-            throw new IllegalStateException(this.toString());
         if (super.addEventListener(listener))
         {
             if (listener instanceof AcceptListener)
@@ -410,8 +408,6 @@ public boolean addEventListener(EventListener listener)
     @Override
     public boolean removeEventListener(EventListener listener)
     {
-        if (isRunning())
-            throw new IllegalStateException(this.toString());
         if (super.removeEventListener(listener))
         {
             if (listener instanceof AcceptListener)