Incorrect animation for bottom-anchored widgets on resize#1

When an AnimatedWrap gets taller as a result of the line length being exceeded, this causes an abrupt change in size. When the wrap is anchored to the top of something, so that the bottom has room to grow, this creates no visible issue, but when it's anchored to the bottom, it results in the top line of the wrap suddenly moving up before the movement animation plays out. This could only be fully solved if the AnimatedWrap were aware of which direction it will be moved when it changes its size. This isn't really possible, but we can often guess the right answer from our alignment parameters. So let's do that.