Fixed another assert in qwindowskeymapper

When we get a WM_CHAR message we do not need to add anything to the key
map as these messages already contain the character code in question.

Task-number: QTBUG-35532

Change-Id: If73993cd873b7c616876b9ba52ceba6b27a6a7b1
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

src/plugins/platforms/windows/qwindowskeymapper.cpp

@@ -743,7 +743,10 @@ bool QWindowsKeyMapper::translateKeyEvent(QWindow *widget, HWND hwnd,
         return true;
     }
 
-    // Add this key to the keymap if it is not present yet.
+    // WM_CHAR messages already contain the character in question so there is
+    // no need to fiddle with our key map. In any other case add this key to the
+    // keymap if it is not present yet.
+    if (msg.message != WM_CHAR)
         updateKeyMap(msg);
 
     MSG peekedMsg;