Defer a twice-asked widget's local redraw to its parent

A span asks a share child twice in one draw: in the room, whose answer
its slots rest on, and in the decided slot, whose cross-axis answer it
reads. The record keeps only the second question, so a local redraw that
found that answer unchanged never told the row that the first had --
seed 946 at depth 6, where emptying a fixed-height column turns it from
a share into a fixed width as wide as the row. A widget its parent asked
more than once in one draw now defers to that parent, like one whose
declared length changed. Pinned as
unsettled::emptying_a_column_the_row_asked_twice_asks_the_row_again.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

core/src/ui/painter.rs

@@ -189,7 +189,8 @@ impl<'a> Painter<'a> {
             diag::region_node(id.id(), self.id, within);
         }
         // A child listed twice would be moved twice.
-        if !self.children.contains(&id.id()) {
+        let re_asked = self.children.contains(&id.id());
+        if !re_asked {
             self.children.push(id.id());
         }
         let px = local.size().to_px(self.px);
@@ -208,6 +209,7 @@ impl<'a> Painter<'a> {
                 place,
                 offer_place: place,
                 narrow,
+                re_asked,
                 px,
             },
             None,