### Godot version

v4.0.3.stable.official [5222a99f5]
Master [6101240231600c871f5c5473872532c68ea3268c] (confirmed by https://github.com/godotengine/godot/issues/77666#issuecomment-1568952502)

### System information

Window 10

### Issue description

References are not unreferenced at the end of `if` scopes.

### Steps to reproduce

Copy, paste and run the snippet below, check the results:

```gdscript
extends Node


func _ready() -> void:
  var ref := RefCounted.new()
  var ref_count : int

  # OK
  ref_count = ref.get_reference_count()
  print('Expected: 1, Result: %d' % ref_count)

  # OK
  if true:
    var temp := ref
    temp = null

  ref_count = ref.get_reference_count()
  print('Expected: 1, Result: %d' % ref_count)

  # FAIL
  if true:
    var temp := ref

  ref_count = ref.get_reference_count()
  print('Expected: 1, Result: %d' % ref_count)
```

Output example:

```
Expected: 1, Result: 1
Expected: 1, Result: 1
Expected: 1, Result: 2
```

### Minimal reproduction project

N/A
clear();
	String source = p_source_code;
	int cursor_line = -1;
	int cursor_column = -1;
	for_completion = p_for_completion;
	int tab_size = 4;
#ifdef TOOLS_ENABLED
	if (EditorSettings::get_singleton()) {
		tab_size = EditorSettings::get_singleton()->get_setting("text_editor/behavior/indent/size");
	}
#endif 
	if (p_for_completion) {
		
		const Vector<String> lines = p_source_code.split("\n");
		cursor_line = 1;
		cursor_column = 1;
		for (int i = 0; i < lines.size(); i++) {
			bool found = false;
			const String &line = lines[i];
			for (int j = 0; j < line.size(); j++) {
				if (line[j] == char32_t(0xFFFF)) {
					found = true;
					break;
				} else if (line[j] == '\t') {
					cursor_column += tab_size - 1;
				}
				cursor_column++;
			}