### 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
{
				
				const GDScriptParser::ClassNode *base_class = codegen.class_node;
				while (base_class != nullptr) {
					if (base_class->has_member(identifier)) {
						const GDScriptParser::ClassNode::Member &member = base_class->get_member(identifier);
						if (member.type == GDScriptParser::ClassNode::Member::FUNCTION || member.type == GDScriptParser::ClassNode::Member::SIGNAL) {
							
							GDScriptCodeGenerator::Address temp = codegen.add_temporary(); 
							GDScriptCodeGenerator::Address self(GDScriptCodeGenerator::Address::SELF);
							gen->write_get_named(temp, identifier, self);
							return temp;
						}
					}
					base_class = base_class->base_type.class_type;
				}
				
				GDScript *scr = codegen.script;
				GDScriptNativeClass *nc = nullptr;
				while (scr) {
					if (scr->native.is_valid()) {
						nc = scr->native.ptr();
					}
					scr = scr->_base;
				}
				if (nc && (ClassDB::has_signal(nc->get_name(), identifier) || ClassDB::has_method(nc->get_name(), identifier))) {
					
					GDScriptCodeGenerator::Address temp = codegen.add_temporary(); 
					GDScriptCodeGenerator::Address self(GDScriptCodeGenerator::Address::SELF);
					gen->write_get_named(temp, identifier, self);