[llvm] [CodeGen] Make hash_value a non-friend function (NFC) (PR #137564)

[Jakub Kuderski via llvm-commits]

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@@ -96,7 +94,7 @@ class Vector {
 inline hash_code hash_value(const Vector &V) {
   const unsigned *VBegin = reinterpret_cast<const unsigned *>(V.begin());
   const unsigned *VEnd = reinterpret_cast<const unsigned *>(V.end());
-  return hash_combine(V.Data.size(), hash_combine_range(VBegin, VEnd));
+  return hash_combine(V.getLength(), hash_combine_range(VBegin, VEnd));
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kuhar wrote:

Would this work?
```suggestion
  return hash_combine(V.getLength(), hash_combine_range(V));
```

https://github.com/llvm/llvm-project/pull/137564