Remove window from mWaitingForDrawn when policy hidden

When doing a wake-and-unlock sequence and the app underneath hides
the status bar, we are dismissing Keyguard, the app gets focus, the
app hides the status bar BUT we haven't finished drawn yet, so we
are waiting until the timeout because w.hasDrawnLw() always returns
false. Remove window from pending list if it gets policy hidden.

Bug: 23431343
Change-Id: I27e8c6d4efb435a4d3b632a4a37c0de5b021c2e7