[FIX] ux3/ToolPopup: Fixed Calculation for Arrow

- if the ToolPopup is potioned too far left (left of the opener) the
corresponding left-position value for the arrow became negative.
- in this case this should be catched and fixed
- now the arrow will be positioned at the most right position of the
ToolPopup if it was opened too far left
- plus the maxWidth calculation has to be processed before it is checked
if the ToolPopup exceeds the window height. Because if there is a
maxWidth this could lead the ToolPopup into changing its height and
therefore it could exceed the browser window

CSS: 0120031469 0000787648 2014
Change-Id: I900507d75f03c34ec1bb0cca3111c8bb60058e74
Merge "[FIX] ux3/ToolPopup: Fixed Calculation for Arrow"