Revert "Updating the scroll calculation from recyclerView to avoid view inflation"

This reverts commit 20bbe95ddb.

Reason for revert: Causing flake in Ironwood test: b/248295569

Test: ABTD
Before: Flaky, 14/50 PASSED
https://android-build.googleplex.com/builds/abtd/run/L33900000956890639

Revert: 50/50 PASSED
https://android-build.googleplex.com/builds/abtd/run/L49200000956887317

Change-Id: I41f4428c74e581323f90c716a7852b5e553ae27d

src/com/android/launcher3/allapps/FloatingHeaderView.java

@@ -68,7 +68,7 @@ public class FloatingHeaderView extends LinearLayout implements
                         mAnimator.cancel();
                     }
 
-                    int current = -mCurrentRV.computeVerticalScrollOffset();
+                    int current = -mCurrentRV.getCurrentScrollY();
                     boolean headerCollapsed = mHeaderCollapsed;
                     moved(current);
                     applyVerticalMove();