[clang] [Clang] avoid assertion in __underlying_type for enum redeclarations (PR #177984)

[Matheus Izvekov via cfe-commits]

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@@ -9891,7 +9891,6 @@ static QualType GetEnumUnderlyingType(Sema &S, QualType BaseType,
     // This is an enum without a fixed underlying type which we skipped parsing
     // the body because we saw its definition previously in another module.
     // Use the definition's integer type in that case.
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mizvekov wrote:

LGTM, but then this comment is not helpful anymore.
```suggestion
```

https://github.com/llvm/llvm-project/pull/177984