bug#21864: 25.0.50; `raise-frame' steals focus some time after being called if the frame was iconified

[Artur Malabarba]

1. On a graphical session, do the following:

    (setq other-frame (make-frame))

2. Iconify (minimize) the newly created frame. 

3. Run the following:

    (let ((cur (selected-frame)))
      (raise-frame other-frame)
      (select-frame cur))

Result: Even though that snippet ends with `(select-frame cur)', focus
is left on `other-frame'.


For comparison, try something else:

1. (setq other-frame (make-frame))

2. Switch back to the original frame, and make sure it is covering the newly 
created frame.

3. Run the following:

    (let ((cur (selected-frame)))
      (raise-frame other-frame)
      (select-frame cur))

Result: other-frame is correctly raised while focus is correctly left on the 
original frame.