[llvm] [CGData] Return ArrayRef<std::string> in getNames (NFC) (PR #140675)

[Matt Arsenault via llvm-commits]

================
@@ -86,7 +86,7 @@ void StableFunctionMapRecord::serialize(raw_ostream &OS,
   support::endian::Writer Writer(OS, endianness::little);
 
   // Write Names.
-  auto &Names = FunctionMap->getNames();
+  auto Names = FunctionMap->getNames();
----------------
arsenm wrote:

```suggestion
  ArrayRef<std::string> Names = FunctionMap->getNames();
```

https://github.com/llvm/llvm-project/pull/140675