Starting window performance tuning for binder block.

- Pass TaskSnapshot to Shell directly.
- Parallel process: create a splash screen worker thread to create the
splash screen view and pre-draw the icon drawable, and use splash
screen thread to do stuff about window's lifecycle like add/remove
window. We don't use shell main thread here so the starting window
won't blocking any task execute on main thread.
- Trigger addStartingWindow directly when startActivity, also
removeStartingWindow directly without post the animation thread.
- Do not defer addStartingWindow for prepare surface, on the contrast
it should be execute before prepare surface.
- Remove ActivityRecordTests#testAddRemoveRace, it wasn't been test as
expected because in original logic the add and remove starting window
are post to animation thread, so the test was actually testing on
handler#postAtFrontOfQueue and handler#removeCallbacks.
For now it will only cause OutOfMemoryError.

Bug: 183665220
Bug: 182836977
Test: atest StartingSurfaceDrawerTests SplashscreenTests
Change-Id: Ie9a529c7d81f07f923394eb69944518f3e9010ce