### 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
push_error(R"(Cannot use simple "@export" annotation with variable without type or initializer, since type can't be inferred.)", p_annotation);
			return false;
		}
		bool is_array = false;
		if (export_type.builtin_type == Variant::ARRAY && export_type.has_container_element_type()) {
			export_type = export_type.get_container_element_type(); 
			is_array = true;
		}
		if (export_type.is_variant() || export_type.has_no_type()) {
			push_error(R"(Cannot use simple "@export" annotation because the type of the initialized value can't be inferred.)", p_annotation);
			return false;
		}
		switch (export_type.kind) {
			case GDScriptParser::DataType::BUILTIN:
				variable->export_info.type = export_type.builtin_type;
				variable->export_info.hint = PROPERTY_HINT_NONE;
				variable->export_info.hint_string = Variant::get_type_name(export_type.builtin_type);
				break;
			case GDScriptParser::DataType::NATIVE:
				if (ClassDB::is_parent_class(export_type.native_type, SNAME("Resource"))) {
					variable->export_info.type = Variant::OBJECT;
					variable->export_info.hint = PROPERTY_HINT_RESOURCE_TYPE;
					variable->export_info.hint_string = export_type.native_type;
				} else if (ClassDB::is_parent_class(export_type.native_type, SNAME("Node"))) {
					variable->export_info.type = Variant::OBJECT;
					variable->export_info.hint = PROPERTY_HINT_NODE_TYPE;
					variable->export_info.hint_string = export_type.native_type;
				} else {
					push_error(R"(Export type can only be built-in, a resource, a node, or an enum.)", variable);
					return false;