[clang] Avoid Assertion Failure Using -fcs-profile-generate with distributed thin-lto (PR #129736)

[Ellis Hoag via cfe-commits]

================
@@ -1334,7 +1334,10 @@ runThinLTOBackend(CompilerInstance &CI, ModuleSummaryIndex *CombinedIndex,
   // Context sensitive profile.
   if (CGOpts.hasProfileCSIRInstr()) {
     Conf.RunCSIRInstr = true;
-    Conf.CSIRProfile = std::move(CGOpts.InstrProfileOutput);
+    Conf.CSIRProfile = CGOpts.InstrProfileOutput.empty()
+                           ? getDefaultProfileGenName()
+                           : std::move(CGOpts.InstrProfileOutput);
+
----------------
ellishg wrote:

Looks like we use `getProfileGenName()` now.

```suggestion
    Conf.CSIRProfile = getProfileGenName(CGOpts)
```

https://github.com/llvm/llvm-project/pull/129736