Add timeout if we dont get onEnterAnimationComplete

Window manager doesn't send us onEnterAnimationComplete in the case
where there are two activites starting at the same time and the
screen orientation is changing. Add a timeout to work around this
until we have a proper fix.

Bug: 23849216
Change-Id: I4be7787d1bc13f8cb0ffd892010c4b5c0142c783