Second Patch for async RenderEngine

- pass a vector of <LayerSettings> instead of a vector of pointers to
drawLayers function to ensure lifecycle safety.
- capture all local variables to call drawLayerInternals in the render
engine thread to avoid of pointers being invalidated if it takes long
time to pop mFunctions calls.
- change renderScreenImplLocked return type as a shared_future
object to unblock SF main thread for screen capture events.
- block region sampling thread only when SF main thread hasn't
completed capture screen event.

Bug: 180657548
Test: SurfaceFlinger_test, android.hardware.graphics.composer@2.2-vts, libcompositionengine_test, librenderengine_test, libsurfaceflinger_unittest pass
Change-Id: I615f2927d30524988fb12df22fe331e7217c3058