Fix for ScrollView absorbing fling stretch

Bug: 288270962

When a fling was absorbed, it wasn't releasing the absorbed
stretch. This CL fixes that.

Test: new tests
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:d8dc760158fe86f314b1c78f596a7a3a18f34bd4)
Merged-In: Id328cb63911eed1644ed2d5e0ee6f2cdc5d4cce8
Change-Id: Id328cb63911eed1644ed2d5e0ee6f2cdc5d4cce8