Correct the target app token for input method window

The root cause is:
There is a defect in window manager service: When a new
activity that can be ime target is added into window manager
but the Z order of input method window don't need to be
changed, then the target app token of input method window
would not be updated to new one. This defect may cause that
the layer of input method window is calculated incorrectly.

The solution:
Correct the target app token for input method window.

Change-Id: I008311e3c9b1cf5fc320b614d8675c183c506d50