WindowManager: Include sigil in RemoteSurfaceTrace format.

ADB may break up some of our writes so we need a sigil
or sizing information to parse on the other end.

Test: cts-tradefed run singleCommand cts -o --module CtsWindowManagerHostTestCases --test android.server.cts.SurfaceViewMovementTests#testSurfaceMovesWithParent
Change-Id: Idcc4cdd4bd8427e4d261567135c74f9a6f0049cc