### 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
consume(GDScriptTokenizer::Token::NEWLINE, R"(Expected a newline after "match" statement.)");
	if (!consume(GDScriptTokenizer::Token::INDENT, R"(Expected an indented block after "match" statement.)")) {
		complete_extents(match);
		return match;
	}
	bool all_have_return = true;
	bool have_wildcard = false;
	while (!check(GDScriptTokenizer::Token::DEDENT) && !is_at_end()) {
		MatchBranchNode *branch = parse_match_branch();
		if (branch == nullptr) {
			advance();
			continue;
		}
#ifdef DEBUG_ENABLED
		if (have_wildcard && !branch->patterns.is_empty()) {
			push_warning(branch->patterns[0], GDScriptWarning::UNREACHABLE_PATTERN);
		}
#endif
		have_wildcard = have_wildcard || branch->has_wildcard;
		all_have_return = all_have_return && branch->block->has_return;
		match->branches.push_back(branch);
	}
	complete_extents(match);
	consume(GDScriptTokenizer::Token::DEDENT, R"(Expected an indented block after "match" statement.)");
	if (all_have_return && have_wildcard) {
		current_suite->has_return = true;
	}
	return match;
}
GDScriptParser::MatchBranchNode *GDScriptParser::parse_match_branch() {