Improve handling of InterruptedException

InterruptedExceptions should be treated as the users intention to
'cancel' the current thread's task. There is no such thing as a
spurious interrupt (not to be confused with "spurious wakeups").

smack-core/src/test/java/org/jivesoftware/smack/DummyConnection.java

@@ -201,7 +201,6 @@ public class DummyConnection extends AbstractXMPPConnection {
             return (P) queue.poll(wait, TimeUnit.SECONDS);
         }
         catch (InterruptedException e) {
-            // TODO handle spurious interrupts
             throw new IllegalStateException(e);
         }
     }

smack-core/src/test/java/org/jivesoftware/smack/test/util/WaitForPacketListener.java

@@ -49,7 +49,6 @@ public class WaitForPacketListener implements PacketListener {
             }
         }
         catch (InterruptedException e) {
-            // TODO better handling of spurious interrupts
             throw new IllegalStateException(e);
         }
     }