int2enum does not work with ASN1 enum types

Summary

There are 2 bugs related to int2enum:

• error of the 2nd operand is reported on the position of the 1st operand
• ASN1 enumerated types are not accepted/recognized when checking the 2nd operand

Titan version

8.3.0

Platform details (OS type and version)

All

/cc @aknappqwt @mmagyari