Splitscreen for minimized state that works with resizable launchers

If a launcher is resizable, going to minimized mode (dock task and then
press home) would show a cropped height of the task at the top in a
minimized state and the fullscreen stack would show the home launcher
which takes the rest of the remaining height. If the launcher is not
resizable, it will default the original behavior.

To enable this in a launcher, add android:resizeableActivity="true" in
the AndroidManifest.xml in the <application/> tag.

Test: manual - rotating while minimized, minimizing using dragging task
or holding overview nav button, installing resizable launcher with a
non-resizable launcher
Fixes: 32504542
Change-Id: Idf4015b40f9bec81b70f146f0f2d7df8ccfb4cf0