[SurfaceFlinger] Resolve deadlock in SurfaceTracing.

SurfaceTracing cannot acquire mStateLock while mDrawingStateLock is
held. SurfaceTracing only needs to acquire mStateLock for getting the
default DisplayDevice for getting a layer's HWC composition type. As a
workaround, grab the DisplayDevice ahead of time.

Bug: 151108871
Test: builds
Change-Id: I84a76694e9890242c666ec5e3eb04d4114f8240a