Otherwise, ODRUniquing would map some member method/variable MDNodes
to have enum type DIScope, resulting in invalid debug info and bad
- Add the check in Verifier that 'scope:' operand could not be enum type.
- Exclude enum type from ODRUniquing when ODR is detected so that the debuginfo/DWARF is well-formed. The other option is to report the error to the user considering this may imply a correctness issue (https://crbug.com/630335) however ODRUniquing doesn't do this currently.