GWT Reflection: Use switch instead of if-cascade

Changed code generation so that a switch is used instead of the if-cascades in the generated code.

New generated code in IReflectionCacheGenerated:

    public Object newInstance (Type type) {
      String param = type.getName();
      switch(param.hashCode()) {
      case -256833987:
          if("com.badlogic.gdx.scenes.scene2d.utils.FocusListener.FocusEvent".equals(param)) {return new com.badlogic.gdx.scenes.scene2d.utils.FocusListener.FocusEvent();}
      break;
      case -1926512153:
          if("com.badlogic.gdx.scenes.scene2d.actions.AlphaAction".equals(param)) {return new com.badlogic.gdx.scenes.scene2d.actions.AlphaAction();}
      break;
    ...