[clang] [llvm] [polly] [IR] Store Triple in Module (NFC) (PR #129868)

[Yingwei Zheng via cfe-commits]

================
@@ -200,7 +200,7 @@ LTOModule::makeLTOModule(MemoryBufferRef Buffer, const TargetOptions &options,
     return EC;
   std::unique_ptr<Module> &M = *MOrErr;
 
-  std::string TripleStr = M->getTargetTriple();
+  std::string TripleStr = M->getTargetTriple().str();
----------------
dtcxzyw wrote:

```
auto Triple = M->getTargetTriple();
if (Triple.empty()) Triple = llvm::Triple(sys::getDefaultTargetTriple());
...
```

https://github.com/llvm/llvm-project/pull/129868