ActionMenuViews always reserve overflow when creating their own menus

ActionMenuViews work in two modes: hosting another Menu instance or
creating their own. The former is used when an action bar is
displaying a window's options menu. The latter is used when an
ActionMenuView (or Toolbar) is placed within an arbitrary layout and
the getMenu method is called.

When showing a window's options menu, ActionMenuPresenter calls into
the ActionBarPolicy to determine if we should reserve an overflow
button or if overflow will be presented by the window instead. Always
reserve overflow if the ActionMenuView is presenting its own menu.

Bug 17381966

Change-Id: I17c495986994d421bf6276ae39ba233243432e97