[dx] warn about deprecated beforeTraverse() method once FileNode is ready #31825

Job	Run time
Commented Code	17s
PHPStan	1m 25s
Active Classes	27s
Preload php-parser Order	16s
Composer Validate	23s
Help and Version	22s
Compatible PHPStan versions	19s
Check fixture classes are different to nodes	26s
Detect composer dependency issues	21s
Check no "*.php" files in rules Fixture directory	19s
Check before/after test fixture on no-changes	24s
Run with Space in Directory	23s
PHP Linter	34s
Finalize classes	25s
	6m 21s

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