### 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
case GDScriptParser::Node::AWAIT: {
			const GDScriptParser::AwaitNode *await = static_cast<const GDScriptParser::AwaitNode *>(p_expression);
			GDScriptCodeGenerator::Address result = codegen.add_temporary(_gdtype_from_datatype(p_expression->get_datatype(), codegen.script));
			GDScriptParser::ExpressionNode *previous_awaited_node = awaited_node;
			awaited_node = await->to_await;
			GDScriptCodeGenerator::Address argument = _parse_expression(codegen, r_error, await->to_await);
			awaited_node = previous_awaited_node;
			if (r_error) {
				return GDScriptCodeGenerator::Address();
			}
			gen->write_await(result, argument);
			if (argument.mode == GDScriptCodeGenerator::Address::TEMPORARY) {
				gen->pop_temporary();
			}
			return result;
		} break;
		
		case GDScriptParser::Node::SUBSCRIPT: {
			const GDScriptParser::SubscriptNode *subscript = static_cast<const GDScriptParser::SubscriptNode *>(p_expression);
			GDScriptCodeGenerator::Address result = codegen.add_temporary(_gdtype_from_datatype(subscript->get_datatype(), codegen.script));
			GDScriptCodeGenerator::Address base = _parse_expression(codegen, r_error, subscript->base);
			if (r_error) {
				return GDScriptCodeGenerator::Address();
			}
			bool named = subscript->is_attribute;
			StringName name;
			GDScriptCodeGenerator::Address index;
			if (p_index_addr.mode != GDScriptCodeGenerator::Address::NIL) {
				index = p_index_addr;
			} else if (subscript->is_attribute) {