[LLDB] Add multi value test for const static enum

1438639a removed a test
that was using undefined behaviour setting a non-typed enum
to a value outside its known range.

That test also checked if we formatted the value properly
when it could contain >1 valid enum value.

I don't think there's anything special about how we format
typed vs non-typed enums so I'm adding a test for ScopedEnum
that will expect to see 2 enum values plus extra.

Reviewed By: labath, Michael137, shafik

Differential Revision: https://reviews.llvm.org/D131472