Remove dead e2e cache assets

The e2e_with_cache workflow was the only consumer of e2eTestRunnerWithCache.php,
applied-rule-removed-node-with-cache/ and timeout-file-not-cached/. They forced
FileCacheStorage via cacheClass() to verify the persisted cache across two runs
on CI; with the storage resolved internally that is no longer possible, so the
workflow and its fixtures go away together.

Author: TomasVotruba