Support for specifying orientation in WindowContainer

Also,
- Fixed failing tests when they are ran as a package vs.
individual classes due to multiple window manager instance.
- Correct some isVisible logic to so a window container that
is invisible is not said to be visible, because one of its
children is visible.

Bug: 30060889
Change-Id: I1bb8730361be2a9f5ce88cd59b7d57d5a459bde6