Use alternate means of detecting enums in `is_udt` This fixes a small regression from https://github.com/rust-lang/rust/pull/155336 Flat enums are excluded from `is_udt` since LLDB natively handles them correctly. The previous logic (`SBType.IsScopedEnumerationType()`) behaved correctly for non-msvc targets, but for some reason on msvc enums don't count as scoped enumerations? The new logic checks the type returned by `SBType.GetEnumerationIntegerType()`. If the queried type isn't an enum, the returned type is invalid. This behaves correctly on both msvc and non-msvc targets, and its behavior doesn't conflict with sum-type enums. As always, testing on msvc isn't really possible atm. That should change soon though =) --- try-job: aarch64-apple