Revert "PriorityNestedScrollConnection: make onStop suspendable and add onCancel"

This reverts commit 5a8343368f5af8c42fb49417514f59210adb6484.

Reason for revert: causes a crash [1]

[1] https://paste.googleplex.com/6223827163152384

Change-Id: I61376765490df4de205d9861c4ae7b89fc1edbbb
9 files changed