Dont switch focus if the dead binder is the last running app
Dont refocus other app if app dies while shell has focus
Stop changing focus when the binder that died was the last app in our list. Fixes: https://bugs.launchpad.net/bugs/1202803.

Approved by PS Jenkins bot, Ricardo Salveti, Michał Sawicz.
Dont refocus other app if app dies while shell has focus. Fixes: https://bugs.launchpad.net/bugs/1178288.

Approved by PS Jenkins bot, Ricardo Salveti, Michał Sawicz.