### 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
ForNode *parse_for();
	IfNode *parse_if(const String &p_token = "if");
	MatchNode *parse_match();
	MatchBranchNode *parse_match_branch();
	PatternNode *parse_match_pattern(PatternNode *p_root_pattern = nullptr);
	WhileNode *parse_while();
	
	ExpressionNode *parse_expression(bool p_can_assign, bool p_stop_on_assign = false);
	ExpressionNode *parse_precedence(Precedence p_precedence, bool p_can_assign, bool p_stop_on_assign = false);
	ExpressionNode *parse_literal(ExpressionNode *p_previous_operand, bool p_can_assign);
	LiteralNode *parse_literal();
	ExpressionNode *parse_self(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_identifier(ExpressionNode *p_previous_operand, bool p_can_assign);
	IdentifierNode *parse_identifier();
	ExpressionNode *parse_builtin_constant(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_unary_operator(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_binary_operator(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_binary_not_in_operator(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_ternary_operator(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_assignment(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_array(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_dictionary(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_call(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_get_node(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_preload(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_grouping(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_cast(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_await(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_attribute(ExpressionNode *p_previous_operand, bool p_can_assign);
	ExpressionNode *parse_subscript(ExpressionNode *p_previous_operand, bool p_can_assign);