### 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
if (p_func) {
		codegen.generator->set_initial_line(p_func->start_line);
	} else {
		codegen.generator->set_initial_line(0);
	}
	GDScriptFunction *gd_function = codegen.generator->write_end();
	if (is_initializer) {
		p_script->initializer = gd_function;
	} else if (is_implicit_initializer) {
		p_script->implicit_initializer = gd_function;
	} else if (is_implicit_ready) {
		p_script->implicit_ready = gd_function;
	}
	if (p_func) {
		
		if (p_func->body->has_return) {
			gd_function->return_type = _gdtype_from_datatype(p_func->get_datatype(), p_script);
		} else {
			gd_function->return_type = GDScriptDataType();
			gd_function->return_type.has_type = true;
			gd_function->return_type.kind = GDScriptDataType::BUILTIN;
			gd_function->return_type.builtin_type = Variant::NIL;
		}
#ifdef TOOLS_ENABLED
		gd_function->default_arg_values = p_func->default_arg_values;
#endif
	}
	if (!is_implicit_initializer && !is_implicit_ready && !p_for_lambda) {
		p_script->member_functions[func_name] = gd_function;
	}