### 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
break;
			default: {
				
				if (s->is_expression()) {
					GDScriptCodeGenerator::Address expr = _parse_expression(codegen, err, static_cast<const GDScriptParser::ExpressionNode *>(s), true);
					if (err) {
						return err;
					}
					if (expr.mode == GDScriptCodeGenerator::Address::TEMPORARY) {
						codegen.generator->pop_temporary();
					}
				} else {
					ERR_FAIL_V_MSG(ERR_INVALID_DATA, "Bug in bytecode compiler, unexpected node in parse tree while parsing statement."); 
				}
			} break;
		}
		gen->clean_temporaries();
	}
	codegen.end_block();
	return OK;
}
GDScriptFunction *GDScriptCompiler::_parse_function(Error &r_error, GDScript *p_script, const GDScriptParser::ClassNode *p_class, const GDScriptParser::FunctionNode *p_func, bool p_for_ready, bool p_for_lambda) {
	r_error = OK;
	CodeGen codegen;
	codegen.generator = memnew(GDScriptByteCodeGenerator);
	codegen.class_node = p_class;
	codegen.script = p_script;
	codegen.function_node = p_func;
	StringName func_name;
	bool is_static = false;