Teardown Tests Should Accept 404 Response for Blob Deletion

[gorkem]

The current teardown tests use the blob delete operation to clean up blobs uploaded during the setup phase. A 404 response is a valid outcome for blob deletion; however, the teardown tests do not currently accept a 404 response.

When running the conformance tests with the OCI_DELETE_MANIFEST_BEFORE_BLOBS=1 environment variable, it is possible for the garbage collection implementation to delete blobs immediately after the manifest is deleted. In such cases, the blobs may no longer exist when the teardown process attempts to delete them, resulting in a 404 response.

To accommodate this scenario, the teardown tests should be updated to expect a 404 response if the manifests are deleted before the blobs.

[sudo-bmitch]

Thanks. That's easy enough to permit. Let us know if #541 resolves it for your registry.

[gorkem]

Thanks for the swift PR. Works perfectly. 🚀