surfaceflinger: use Mutex timedLock instead of tryLock loop

Rather than trying to acquire the state lock without waiting three
times at 1 second intervals in SurfaceFlinger::dump(), just try to
acquire the lock once with a 1 second timeout. Avoids spurious mutex
acquire failures that lead to flaky
com.android.cts.jank.opengl.CtsHostJankOpenGl results.

Bug: 18842510
Change-Id: I00ce6109647de2aef8831dd2f8fa98652ba7f4e0