[clang] Add Clang attribute to ensure that fields are initialized explicitly (PR #102040)

[Erich Keane via cfe-commits]

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@@ -5214,9 +5215,9 @@ unsigned RecordDecl::getODRHash() {
   // Only calculate hash on first call of getODRHash per record.
   ODRHash Hash;
   Hash.AddRecordDecl(this);
-  // For RecordDecl the ODRHash is stored in the remaining 26
-  // bit of RecordDeclBits, adjust the hash to accomodate.
-  setODRHash(Hash.CalculateHash() >> 6);
+  // For RecordDecl the ODRHash is stored in the remaining
+  // bit of RecordDeclBits, adjust the hash to accommodate.
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erichkeane wrote:

```suggestion
  // bits of RecordDeclBits, adjust the hash to accommodate.
```

https://github.com/llvm/llvm-project/pull/102040