Match items in icon preview with items in Folder using permutations.

Before, with the FolderIconPreviewVerifier, we would
adjust which items are displayed in the FolderIcon.
This caused some issues where the apps in the folder
icon would jump to whatever was in the upper left quadrant.

Now, we always display the 4 first items in the icon by
modifying the XY positions of the items within the Folder.

Bug: 27944225
Bug: 35064148
Change-Id: I46c0fbb064d4da4da155e29963bfb92b14e40f07

src/com/android/launcher3/Workspace.java

@@ -3792,7 +3792,7 @@ public class Workspace extends PagedView
                 ItemInfo info = (ItemInfo) item.getTag();
                 if (recurse && info instanceof FolderInfo && item instanceof FolderIcon) {
                     FolderIcon folder = (FolderIcon) item;
-                    ArrayList<View> folderChildren = folder.getFolder().getItemsInReadingOrder();
+                    ArrayList<View> folderChildren = folder.getFolder().getItemsInRankOrder();
                     // map over all the children in the folder
                     final int childCount = folderChildren.size();
                     for (int childIdx = 0; childIdx < childCount; childIdx++) {