[clang] [Clang][NFC] Remove duplicated specialization of `llvm::DenseMapInfo<llvm::FoldingSetNodeID>` (PR #159718)

[Timm Baeder via cfe-commits]

================
@@ -3843,4 +3843,25 @@ typename clang::LazyGenerationalUpdatePtr<Owner, T, Update>::ValueType
   return Value;
 }
 
+template <> struct llvm::DenseMapInfo<llvm::FoldingSetNodeID> {
+  static FoldingSetNodeID getEmptyKey() { return FoldingSetNodeID{}; }
+
+  static FoldingSetNodeID getTombstoneKey() {
+    FoldingSetNodeID ID;
+    for (size_t i = 0; i < sizeof(ID) / sizeof(unsigned); ++i) {
----------------
tbaederr wrote:

```suggestion
    for (size_t I = 0; I != sizeof(ID) / sizeof(unsigned); ++I) {
```

https://github.com/llvm/llvm-project/pull/159718