Laravel 5.6 updates

Travis config update

Removed HHVM script as Laravel no longer support HHVM after releasing 5.3

vendor/symfony/event-dispatcher/Debug/TraceableEventDispatcher.php

@@ -32,6 +32,7 @@ class TraceableEventDispatcher implements TraceableEventDispatcherInterface
     private $called;
     private $dispatcher;
     private $wrappedListeners;
+    private $orphanedEvents;
 
     public function __construct(EventDispatcherInterface $dispatcher, Stopwatch $stopwatch, LoggerInterface $logger = null)
     {
@@ -40,6 +41,7 @@ class TraceableEventDispatcher implements TraceableEventDispatcherInterface
         $this->logger = $logger;
         $this->called = array();
         $this->wrappedListeners = array();
+        $this->orphanedEvents = array();
     }
 
     /**
@@ -207,9 +209,15 @@ class TraceableEventDispatcher implements TraceableEventDispatcherInterface
         return $notCalled;
     }
 
+    public function getOrphanedEvents(): array
+    {
+        return $this->orphanedEvents;
+    }
+
     public function reset()
     {
         $this->called = array();
+        $this->orphanedEvents = array();
     }
 
     /**
@@ -247,6 +255,12 @@ class TraceableEventDispatcher implements TraceableEventDispatcherInterface
 
     private function preProcess($eventName)
     {
+        if (!$this->dispatcher->hasListeners($eventName)) {
+            $this->orphanedEvents[] = $eventName;
+
+            return;
+        }
+
         foreach ($this->dispatcher->getListeners($eventName) as $listener) {
             $priority = $this->getListenerPriority($eventName, $listener);
             $wrappedListener = new WrappedListener($listener, null, $this->stopwatch, $this);