Made creation of multiple stacks more intentional.

Previous it was unintentional due to the following fixes:
- Made ACTIVITY_TYPE_UNDEFINED compatible with stacks of
ACTIVITY_TYPE_STANDARD. Any request to create an undefined stack type
ends up creates a standard type, so it makes sense for them to be
compatible.
- Made standard types of WINDOWING_MODE_UNDEFINED compatible with the
display's windowing mode. Any request to cerate a stack in an undefined
windowing mode end up creating a stack in the display's windowing mode.
- Added 'dumspys activity containers' for dumping the activity
hierarchy.
Now it is more intentional where we always create a stack for specific
stack activity types and windowing modes when getOrCreateStack is
called.

Bug: 67747409
Bug: 64146578
Test: go/wm-test
Test: Existing tests pass

Change-Id: I85935e8681113a0c06dfc15ef9891e3f91b98a02