### 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 (subscript->base->type == GDScriptParser::Node::SELF && codegen.script) {
					GDScriptParser::IdentifierNode *identifier = subscript->attribute;
					HashMap<StringName, GDScript::MemberInfo>::Iterator MI = codegen.script->member_indices.find(identifier->name);
#ifdef DEBUG_ENABLED
					if (MI && MI->value.getter == codegen.function_name) {
						String n = identifier->name;
						_set_error("Must use '" + n + "' instead of 'self." + n + "' in getter.", identifier);
						r_error = ERR_COMPILATION_FAILED;
						return GDScriptCodeGenerator::Address();
					}
#endif
					if (MI && MI->value.getter == "") {
						
						gen->pop_temporary();
						
						return GDScriptCodeGenerator::Address(GDScriptCodeGenerator::Address::MEMBER, MI->value.index, _gdtype_from_datatype(subscript->get_datatype(), codegen.script));
					}
				}
				name = subscript->attribute->name;
				named = true;
			} else {
				if (subscript->index->is_constant && subscript->index->reduced_value.get_type() == Variant::STRING_NAME) {
					
					name = subscript->index->reduced_value;
					named = true;
				} else {
					
					index = _parse_expression(codegen, r_error, subscript->index);
					if (r_error) {
						return GDScriptCodeGenerator::Address();