Non-repeatable reads when data is lost

When an entry `k=v` is lost and partition handling is disabled, `cache.get(k)` will return `null`.

However, a second `cache.get(k)` in the same transaction could return a non-null value, because the `AllOwnersLostException` is only handled in `StateTransferInterceptor`, and STI doesn't put the null value in the context.