Don't repeat ReorderPreviewAnimation for folders/widgets in power save mode.

Since power save mode (introduced in Lollipop, also known as battery saver)
disables animations, the ReorderPreviewAnimation looks bad - instead of
displaced folders subtly and smoothly moving up and down, they violently jump
between up and down positions in rapid succession. Setting the animation to not
repeat in this case avoids this issue.

Bug: 23675090
Change-Id: I8149610af75e7023dca28a942b3447228083cd33