Some rel data type does not implement the digest correctly

Some of the rel data types for legacy planner:

• GenericRelDataType
• ArrayRelDataType
• MapRelDataType
• MultisetRelDataType

Does not implement the digest correctly, especially for GenericRelDataType , the RelDataTypeFactory caches the type instances based on its digest, a wrong digest impl would mess up the type instance creation, e.g. without this patch, all the GenericRelDataType instances have same digest `ANY`.