Don't specify stack bounds for unsizeable home stack in dock mode

Doing so will put the stack in multi-window mode which means it
can't affect the device orientation which can cause the app to
to put in a configuration it doesn't support when in split-screen
multi-window mode.

Test: manual
Change-Id: I9f08187d8880c8f2b486f477123342a9a2f7effc
Fixes: 37334914