Reverted change in how hack works (#12727, #12736)

The fix for Window slightly altered how the hack was done, breaking #12736

Change-Id: I2d33b45421c40ce011d2e728a573f7572e326c47

client/src/com/vaadin/client/Util.java

@@ -556,10 +556,10 @@ public class Util {
                     final String oldHeight = scrollable.getStyle().getHeight();
 
                     scrollable.getStyle().setWidth(110, Unit.PCT);
-                    scrollable.getStyle().setHeight(110, Unit.PCT);
                     scrollable.getOffsetWidth();
-                    scrollable.getOffsetHeight();
                     scrollable.getStyle().setProperty("width", oldWidth);
+                    scrollable.getStyle().setHeight(110, Unit.PCT);
+                    scrollable.getOffsetHeight();
                     scrollable.getStyle().setProperty("height", oldHeight);
 
                     // Restore the scroll position