[paulbalandan]

Description
Fixes a flaky InfoCacheTest::testInfoCacheCanSeeFoo in the random test execution workflow, where cache:info printed an empty table after foo was saved.

testSaveMode replaced $this->handler with one using the default writable/cache/ path. tearDown() then called clean() on that handler, which deletes recursively, so it removed the files of any other test using a subdirectory of writable/cache/. The workflow runs components in parallel, so this could hit the Commands tests while Cache was running.

The test now uses $this->config, which already points at the test's own directory.

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