### 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
GDScriptParser::DataType member_t = p_node->datatype;
	GDScriptParser::DataType init_t = p_node->initializer->datatype;
	if (member_t.is_hard_type() && init_t.is_hard_type() &&
			member_t.kind == GDScriptParser::DataType::BUILTIN && init_t.kind == GDScriptParser::DataType::BUILTIN) {
		if (Variant::can_convert_strict(init_t.builtin_type, member_t.builtin_type)) {
			Variant *v = &p_node->initializer->reduced_value;
			Callable::CallError ce;
			Variant::construct(member_t.builtin_type, p_variant, const_cast<const Variant **>(&v), 1, ce);
		}
	}
}
void GDScriptCompiler::make_scripts(GDScript *p_script, const GDScriptParser::ClassNode *p_class, bool p_keep_state) {