Drop WaylandServer::dispatch()

There's no any good reason to dispatch events at shutdown.

autotests/integration/kwin_wayland_test.cpp

@@ -83,7 +83,6 @@ WaylandTestApplication::~WaylandTestApplication()
     delete m_xwayland;
     m_xwayland = nullptr;
     destroyWorkspace();
-    waylandServer()->dispatch();
     if (QStyle *s = style()) {
         s->unpolish(this);
     }

src/main_wayland.cpp

@@ -130,7 +130,6 @@ ApplicationWayland::~ApplicationWayland()
     delete m_xwayland;
     m_xwayland = nullptr;
     destroyWorkspace();
-    waylandServer()->dispatch();
 
     if (QStyle *s = style()) {
         s->unpolish(this);

src/wayland_server.cpp

@@ -703,14 +703,6 @@ void WaylandServer::removeClient(AbstractClient *c)
     Q_EMIT shellClientRemoved(c);
 }
 
-void WaylandServer::dispatch()
-{
-    if (!m_display) {
-        return;
-    }
-    m_display->dispatchEvents();
-}
-
 static AbstractClient *findClientInList(const QList<AbstractClient *> &clients, const KWaylandServer::SurfaceInterface *surface)
 {
     auto it = std::find_if(clients.begin(), clients.end(),

src/wayland_server.h

@@ -185,7 +185,6 @@ public:
     KWaylandServer::ClientConnection *screenLockerClientConnection() const {
         return m_screenLockerClientConnection;
     }
-    void dispatch();
 
     /**
      * Struct containing information for a created Wayland connection through a