### 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
StringName class_name;
									if (base.type.kind == GDScriptDataType::NATIVE) {
										class_name = base.type.native_type;
									} else {
										class_name = base.type.native_type == StringName() ? base.type.script_type->get_instance_base_type() : base.type.native_type;
									}
									if (ClassDB::class_exists(class_name) && ClassDB::has_method(class_name, call->function_name)) {
										MethodBind *method = ClassDB::get_method(class_name, call->function_name);
										if (_can_use_ptrcall(method, arguments)) {
											
											gen->write_call_ptrcall(result, base, method, arguments);
										} else {
											
											gen->write_call_method_bind(result, base, method, arguments);
										}
									} else {
										gen->write_call(result, base, call->function_name, arguments);
									}
								} else if (base.type.has_type && base.type.kind == GDScriptDataType::BUILTIN) {
									gen->write_call_builtin_type(result, base, base.type.builtin_type, call->function_name, arguments);
								} else {
									gen->write_call(result, base, call->function_name, arguments);
								}
								if (base.mode == GDScriptCodeGenerator::Address::TEMPORARY) {
									gen->pop_temporary();
								}
							}
						} else {
							_set_error("Cannot call something that isn't a function.", call->callee);