MenuButton Label dissapears when a shortcut is set.

[coppolaemilio]

Godot version:
Latest from: https://hugo.pro/projects/godot-builds/ (v3.1.beta.calinou.c21ca98)

OS/device including version:
Windows 10

Issue description:
MenuButton items lose the label when a shortcut is set.

Steps to reproduce:

1. Create new scene with a Control node as the root
2. Add MenuButton node
3. Add this code to the root node:

extends Control

func _ready():
	# Add items
	$MenuButton.get_popup().add_item("I'm a regular item")
	$MenuButton.get_popup().add_item("I am not")
	
	# Create the shortcut
	var shortcut = ShortCut.new()
	var inputeventkey = InputEventKey.new()
	inputeventkey.set_scancode(KEY_Q)
	inputeventkey.control = true
	shortcut.set_shortcut(inputeventkey)
	
	# Set shortcut
	$MenuButton.get_popup().set_item_shortcut(1, shortcut, true)

4. Run project and check how the label on the second menu item is gone.

Minimal reproduction project:
MenuButtonItemBug.zip

[akien-mga]

Reopening as #25841 is being reverted.

[akien-mga]

For the reference, the fixes proposed so far (#25841, #25902) were insufficient, as it appears that the editor uses this "bug" as a feature.

See e.g. this debug output for the "Scene" popup menu:

diff --git a/scene/gui/popup_menu.cpp b/scene/gui/popup_menu.cpp
index a7c6c5cca..f13d74d96 100644
--- a/scene/gui/popup_menu.cpp
+++ b/scene/gui/popup_menu.cpp
@@ -520,6 +520,13 @@ void PopupMenu::_notification(int p_what) {
                                }
 
                                String text = items[i].shortcut.is_valid() ? String(tr(items[i].shortcut->get_name())) : items[i].xl_text;
+                               {
+                                       // debug stuff
+                                       print_line("--------");
+                                       print_line("xl_text: " + items[i].xl_text);
+                                       print_line("shortcut name: " + (items[i].shortcut.is_valid() ? tr(items[i].shortcut->get_name()) : "[No shortcut]"));
+                                       print_line("shortcut as text: " + _get_accel_text(i));
+                               }
 
                                item_ofs.x += items[i].h_ofs;
                                if (items[i].separator) {

--------
xl_text: 
shortcut name: New Scene
shortcut as text: None
--------
xl_text: 
shortcut name: New Inherited Scene...
shortcut as text: None
--------
xl_text: 
shortcut name: Open Scene...
shortcut as text: Control+O
--------
xl_text: 
shortcut name: Reopen Closed Scene
shortcut as text: Control+Shift+T
--------
xl_text: Open Recent
shortcut name: [No shortcut]
shortcut as text: 
--------
xl_text: 
shortcut name: [No shortcut]
shortcut as text: 
--------
xl_text: 
shortcut name: Save Scene
shortcut as text: Control+S
--------
xl_text: 
shortcut name: Save Scene As...
shortcut as text: Control+Shift+S
--------
xl_text: 
shortcut name: Save All Scenes
shortcut as text: Control+Shift+Alt+S
--------
xl_text: 
shortcut name: [No shortcut]
shortcut as text: 
--------
xl_text: 
shortcut name: Quick Open...
shortcut as text: Shift+Alt+O
--------
xl_text: 
shortcut name: Quick Open Scene...
shortcut as text: Control+Shift+O
--------
xl_text: 
shortcut name: Quick Open Script...
shortcut as text: Control+Alt+O
--------
xl_text: 
shortcut name: [No shortcut]
shortcut as text: 
--------
xl_text: Convert To...
shortcut name: [No shortcut]
shortcut as text: 
--------
xl_text: 
shortcut name: [No shortcut]
shortcut as text: 
--------
xl_text: 
shortcut name: Undo
shortcut as text: Control+Z
--------
xl_text: 
shortcut name: Redo
shortcut as text: Control+Shift+Z
--------
xl_text: 
shortcut name: [No shortcut]
shortcut as text: 
--------
xl_text: 
shortcut name: Revert Scene
shortcut as text: None
--------
xl_text: 
shortcut name: Close Scene
shortcut as text: Control+Shift+W
--------
xl_text: 
shortcut name: [No shortcut]
shortcut as text: 
--------
xl_text: 
shortcut name: Quit
shortcut as text: Control+Q

Only two of the above have a valid xl_text, while others rely on the shortcut name.