gtktiledviewer: use setView() before postKeyEvent()

Also in SfxLokHelper::setView() set the current view shell directly,
GetFocus() in VCL may be a NOP for hidden windows.

With this, the Writer layout dump shows that two Gtk windows can have
different cursor positions correctly.

(cherry picked from commit f2e55ea1)

Conflicts:
	libreofficekit/source/gtk/lokdocview.cxx

Change-Id: I81890c1d8ad7972f1194db3d5f2e9d8a39fc2f87

sfx2/source/view/lokhelper.cxx

@@ -46,7 +46,7 @@ void SfxLokHelper::setView(size_t nId)
 
     SfxViewShell* pViewShell = rViewArr[nId];
     if (SfxViewFrame* pViewFrame = pViewShell->GetViewFrame())
-        pViewFrame->GetWindow().GrabFocus();
+        pViewFrame->MakeActive_Impl(false);
 }
 
 size_t SfxLokHelper::getView()