NewFuseTestFramework dropped its config argument and Cleanup read a fresh
DefaultTestConfig, so SkipCleanup never did anything. Cleanup also skipped
teardown whenever TEST_SKIP_CLUSTER_SETUP was set, even when TEST_MOUNT_POINT
was empty and Setup had started the cluster itself. The framework now keeps
the config it was built with, runs external-mount tests inside a per-run work
dir under the mount, and only skips teardown when an external mount was
actually used.
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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>