[llvm] [NFCI][BitcodeReader]Read real GUID from VI as opposed to storing it in map (PR #107735)

[Kazu Hirata via llvm-commits]

================
@@ -943,10 +943,8 @@ class ModuleSummaryIndexBitcodeReader : public BitcodeReaderBase {
   // they are recorded in the summary index being built.
   // We save a GUID which refers to the same global as the ValueInfo, but
   // ignoring the linkage, i.e. for values other than local linkage they are
-  // identical (this is the second tuple member).
-  // The third tuple member is the real GUID of the ValueInfo.
-  DenseMap<unsigned,
-           std::tuple<ValueInfo, GlobalValue::GUID, GlobalValue::GUID>>
+  // identical (this is the second tuple member). ValueInfo has the real GUID.
----------------
kazutakahirata wrote:

Maybe drop `tuple`?
```suggestion
  // identical (this is the second member). ValueInfo has the real GUID.
```

https://github.com/llvm/llvm-project/pull/107735