Revert^2 "Moving rearrangementExists to ReorderLogic since it's only used there"

This reverts commit 484a7ea4f3.

Reason for revert: Fixing build error 

Change-Id: I00dcbb831dc40a90d43ada7315969251413bb88b

src/com/android/launcher3/MultipageCellLayout.java

@@ -120,7 +120,7 @@ public class MultipageCellLayout extends CellLayout {
     }
 
     @Override
-    public void copyCurrentStateToSolution(ItemConfiguration solution, boolean temp) {
+    public void copyCurrentStateToSolution(ItemConfiguration solution) {
         int childCount = mShortcutsAndWidgets.getChildCount();
         for (int i = 0; i < childCount; i++) {
             View child = mShortcutsAndWidgets.getChildAt(i);