### 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
codegen.generator->write_newline(field->initializer->start_line);
			GDScriptCodeGenerator::Address src_address = _parse_expression(codegen, r_error, field->initializer, false, true);
			if (r_error) {
				memdelete(codegen.generator);
				return nullptr;
			}
			GDScriptDataType field_type = _gdtype_from_datatype(field->get_datatype(), codegen.script);
			GDScriptCodeGenerator::Address temp = codegen.add_temporary(field_type);
			if (field->use_conversion_assign) {
				codegen.generator->write_assign_with_conversion(temp, src_address);
			} else {
				codegen.generator->write_assign(temp, src_address);
			}
			if (src_address.mode == GDScriptCodeGenerator::Address::TEMPORARY) {
				codegen.generator->pop_temporary();
			}
			codegen.generator->write_set_static_variable(temp, class_addr, p_script->static_variables_indices[field->identifier->name].index);
			codegen.generator->pop_temporary();
		}
	}
	if (p_script->has_method(GDScriptLanguage::get_singleton()->strings._static_init)) {
		codegen.generator->write_newline(p_class->start_line);
		codegen.generator->write_call(GDScriptCodeGenerator::Address(), class_addr, GDScriptLanguage::get_singleton()->strings._static_init, Vector<GDScriptCodeGenerator::Address>());
	}
#ifdef DEBUG_ENABLED
	if (EngineDebugger::is_active()) {
		String signature;
		
		if (!p_script->get_script_path().is_empty()) {