### 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
assignment->operation = AssignmentNode::OP_DIVISION;
			assignment->variant_op = Variant::OP_DIVIDE;
			break;
		case GDScriptTokenizer::Token::PERCENT_EQUAL:
			assignment->operation = AssignmentNode::OP_MODULO;
			assignment->variant_op = Variant::OP_MODULE;
			break;
		case GDScriptTokenizer::Token::LESS_LESS_EQUAL:
			assignment->operation = AssignmentNode::OP_BIT_SHIFT_LEFT;
			assignment->variant_op = Variant::OP_SHIFT_LEFT;
			break;
		case GDScriptTokenizer::Token::GREATER_GREATER_EQUAL:
			assignment->operation = AssignmentNode::OP_BIT_SHIFT_RIGHT;
			assignment->variant_op = Variant::OP_SHIFT_RIGHT;
			break;
		case GDScriptTokenizer::Token::AMPERSAND_EQUAL:
			assignment->operation = AssignmentNode::OP_BIT_AND;
			assignment->variant_op = Variant::OP_BIT_AND;
			break;
		case GDScriptTokenizer::Token::PIPE_EQUAL:
			assignment->operation = AssignmentNode::OP_BIT_OR;
			assignment->variant_op = Variant::OP_BIT_OR;
			break;
		case GDScriptTokenizer::Token::CARET_EQUAL:
			assignment->operation = AssignmentNode::OP_BIT_XOR;
			assignment->variant_op = Variant::OP_BIT_XOR;
			break;
		default:
			break; 
	}