Fix wallpaper cropped too soon when unminimizing dock

Set adjusted bounds on the stack that's side-by-side to the docked
stack, so that TaskStack.getDimBounds returns the adjusted bounds
during unminimizing dock animation. This way wallpaper is not cropped
too soon to the final stack bounds.

The adjusted bounds won't be used for alignment for minimizing.

bug: 28763785
Change-Id: Ifea4366dd4b1bd35f2ed720dd1819a10bdfd86fa