### 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
return err;
						}
					}
					
					gen->write_if(pattern_result);
					
					gen->pop_temporary();
					
					err = _parse_block(codegen, branch->block, false); 
					if (err) {
						return err;
					}
					codegen.end_block(); 
				}
				
				for (int j = 0; j < match->branches.size(); j++) {
					gen->write_endif();
				}
			} break;
			case GDScriptParser::Node::IF: {
				const GDScriptParser::IfNode *if_n = static_cast<const GDScriptParser::IfNode *>(s);
				GDScriptCodeGenerator::Address condition = _parse_expression(codegen, err, if_n->condition);
				if (err) {
					return err;
				}
				gen->write_if(condition);
				if (condition.mode == GDScriptCodeGenerator::Address::TEMPORARY) {
					codegen.generator->pop_temporary();
				}
				err = _parse_block(codegen, if_n->true_block);