Get window info debug data without holding the statelock

Avoids a deadlock with mStateLock when calling dumpsys
SurfaceFlinger. Deadlock happens because we make a blocking
call into the background thread holding the mStateLock. Background
thread may try to hold the mStateLock when destroying a layer handle
which can result in a deadlock.

Flag: EXEMPT bugfix
Test: presubmit, run dumpsys
Fixes: 347142017
Change-Id: Icda6d4ee0ead70a4d76a4f6fe766fdf40bae6d2c