Replace Long.compare() with implementation.

- Long.compare() was added in API level 19.

Change-Id: Ic7020c941403c10daa6feacdc737c6a82676ada0
diff --git a/src/com/android/launcher3/LauncherModel.java b/src/com/android/launcher3/LauncherModel.java
index 1b0b3a4..a0e287a 100644
--- a/src/com/android/launcher3/LauncherModel.java
+++ b/src/com/android/launcher3/LauncherModel.java
@@ -2387,7 +2387,7 @@
             Collections.sort(allWorkspaceItems, new Comparator<ItemInfo>() {
                 @Override
                 public int compare(ItemInfo lhs, ItemInfo rhs) {
-                    return Long.compare(lhs.container, rhs.container);
+                    return Utilities.longCompare(lhs.container, rhs.container);
                 }
             });
             for (ItemInfo info : allWorkspaceItems) {
@@ -2469,7 +2469,7 @@
                             lhs.cellY * cellCountX + lhs.cellX);
                     long rr = (rhs.container * containerOffset + rhs.screenId * screenOffset +
                             rhs.cellY * cellCountX + rhs.cellX);
-                    return Long.compare(lr, rr);
+                    return Utilities.longCompare(lr, rr);
                 }
             });
         }