Expandable node is shown at wrong place, sorting broken after expand

If items limit is enabled, clicking on expandable element adds all
elements **before** the node, so the sort order is totally wrong and
"expandable node" appears "in the middle" of the siblings.

However, "hidden and now expanded" elements (if exists) should always be
appended **to the end** of the shown children.

This is a regression from 5930a51 /
#1331.

The problem with the patch above is that it inserts all previously
hidden elements at the zero index in the tree, but the tree **has
already some children**, so instead of adding new elements below
existing, the patch prepends them.

Since #1331
consists of only two changes (changed tree item creation order on expand
and updated javadoc), this is revert the former one.

Fixes #1417

Author: iloveeclipse

bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java

@@ -1151,9 +1151,8 @@ void handleExpandableNodeClicked(Widget w) {
 			item.dispose();
 
 			// create children on parent
-			// For performance insert every item at index 0 (in reverse order):
-			for (int i = children.length - 1; i >= 0; i--) {
-				createTreeItem(parent, children[i], 0);
+			for (Object element : children) {
+				createTreeItem(parent, element, -1);
 			}
 
 			// reset the selection. client's selection listener should not be triggered.