Delay visible of rotation enter animation

At the beginning of rotation animation, because the screenshot is
almost opaque, it doesn't need to draw all real surfaces at the
same time.

Bug: 439946818
Flag: com.android.window.flags.no_alpha_rotation_enter_animation
Test: ftrace_events: "gpu_mem/gpu_mem_total"
Change-Id: I1c8f8a73a2b6b8893405e6a9864e95fce87e6b46