Move back up before starting another test for longer vertical movement.

Note that depending on the touch slop value, the distance by which we move down differs, and we need to move back up before starting another test.
Otherwise, we might have already reached the bottom without any space left to register the touch.
Also adding the touch slop value to the distance moved for "too far distance," so it is proportional to the touch slop value.

Bug: 141298890
Test: ScrollingMovementMethodTest all passing on Volvo IHU and on Pixel 2.
Change-Id: I54c58415c2c7285069581c1326113b15053cee1f