rtpjitterbuffer: If we have an immediate timeout, don't try to find an earlier timeout

If we have lots of such immediate timeouts, we would otherwise have quadratic
runtime in the number of timeouts.

gst/rtpmanager/gstrtpjitterbuffer.c

@@ -3315,6 +3315,10 @@ wait_next_timeout (GstRtpJitterBuffer * jitterbuffer)
         GST_DEBUG_OBJECT (jitterbuffer, "new best %d", i);
         timer = test;
         timer_timeout = test_timeout;
+
+        /* Immediate timeout */
+        if (test_timeout == -1)
+          break;
       }
     }
     if (timer && !priv->blocked) {