Fix unhashable cache key error.

[chinazhangchao]

Some cases the cache key is unhashable. For example:

• There's no column files (e.g. AMD), so the conditions is not filtered and there are some nparray type values in the conditions which is not hashable.
• Some ops (e.g. CumSum) have nparray type values in the conditions. The root cause investigation is still in progress.

[chinazhangchao]

Replace with #366