Remove Overview atomic animation support

- Remove PLAY_ATOMIC_OVERVIEW_SCALE and PLAY_ATOMIC_OVERVIEW_PEEK
- Remove complicated parallel atomic animation support from
  AbstractStateChangeTouchController and subclasses
- Remove some code related to going between Overview <-> AllApps

Test: Swipe between states in all 3 navigation modes
Bug: 175137718
Change-Id: Ice314d46946c3a983cdc6ccf1a67effb5da9156e

quickstep/src/com/android/launcher3/statehandlers/BackButtonAlphaHandler.java

@@ -48,10 +48,6 @@ public class BackButtonAlphaHandler implements StateHandler<LauncherState> {
     @Override
     public void setStateWithAnimation(LauncherState toState, StateAnimationConfig config,
             PendingAnimation animation) {
-        if (config.onlyPlayAtomicComponent()) {
-            return;
-        }
-
         if (SysUINavigationMode.getMode(mLauncher) != TWO_BUTTONS) {
             return;
         }