Verbose touch debugging for the status bar.

This resurrects some truly ancient code (2012!) to
understand how users interact with the shade open gesture.
It turns out to be a convenient way to get logs for b/178277858, in which the notification shade simply won't be pulled down in some situations.

Bug: 178277858
Test: touch status bar; watch `adb logcat -b events`
Test: adb shell dumpsys activity service com.android.systemui ; \
      adb pull /data/user_de/0/com.android.systemui/cache/statusbar_gestures.dat
Change-Id: I2a0d66159c23dd68437b5e750309ae134e3797b7