Fix #119384: Update Sharing Objects When Changing Modes

When toggling one object in and out of edit mode, we need to update
the edit mode flag on all objects sharing the same data. Otherwise
some unrelated object might be in OB_MODE_EDIT but suddenly lose their
data->edit_mesh. These being out sync can cause various crashes. This
also corrects the icon shown in Outliner when another object is in edit
mode that shares its data.

@@ -2178,6 +2178,11 @@ static void outliner_draw_mode_column_toggle(uiBlock *block,
   const bool object_data_shared = (ob->data == ob_active->data);
   draw_active_icon = draw_active_icon || object_data_shared;
 
+  if (!draw_active_icon && BKE_object_is_in_editmode(ob)) {

@@ -94,2 +94,4 @@
     if (changed) {
       ED_object_base_select(base, BA_DESELECT);
+      /* All objects sharing this same data have to come out of edit mode. */
+      LISTBASE_FOREACH (Object *, obtest, &bmain->objects) {

@@ -96,0 +96,4 @@
+      /* All objects sharing this same data have to come out of edit mode. */
+      LISTBASE_FOREACH (Object *, obtest, &bmain->objects) {
+        if (obtest->data == ob->data) {
+          obtest->mode &= ~OB_MODE_EDIT;