test: fix flaky CommandsTest override-discovery tests under random order

[paulbalandan]

Description

CommandsTest::testDiscoveredLegacyCommandsCanBeOverridden (and its modern counterpart) fail intermittently under --order-by=random on GHA. Reproducer: vendor/bin/phpunit tests/system/CLI --order-by=random --random-order-seed=1777101167, which produces:

1) CodeIgniter\CLI\CommandsTest::testDiscoveredLegacyCommandsCanBeOverridden
Failed asserting that '
CodeIgniter Version: 4.8.0-dev
' [ASCII](length: 32) contains "This is App\Commands\AppInfo" [ASCII](length: 28).

/home/runner/work/CodeIgniter4/CodeIgniter4/tests/system/CLI/CommandsTest.php:451

The override tests copy a fixture into app/Commands/ and expect discovery to pick it up. app/Commands/ is not tracked in git, so on a fresh checkout it does not exist until the test creates it.

PHP keys its stat cache by exact path string and only invalidates the exact path argument passed to mkdir/copy/unlink. The test's copyCommand calls mkdir(APPPATH . 'Commands') (no trailing slash), but FileLocator::listFiles() later checks is_dir(APPPATH . 'Commands/') (with trailing slash). When an earlier CLI test in the random order primes the cache with the trailing-slash form while the directory does not yet exist, the stat-cache entry survives the mkdir. Discovery then skips the App namespace and the original fixture command wins the app:info slot, so the override assertion fails.

Calling clearstatcache(true) after the filesystem mutations clears both the stat cache and the realpath cache, so subsequent discovery sees the fresh state. Scoped to the test fixture; production behavior matches PHP's documented cache rules and is not changed here.

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value (without duplication)
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide