[llvm] [DFAJumpThreading] Rewrite the way paths are enumerated (PR #96127)

[via llvm-commits]

================
@@ -617,21 +713,32 @@ struct AllSwitchPaths {
       if (!Successors.insert(Succ).second)
         continue;
 
-      // Found a cycle through the SwitchBlock
-      if (Succ == SwitchBlock) {
-        Res.push_back({BB});
+      // Found a cycle through the final block.
+      if (Succ == ToBB) {
+        PathType NewPath;
+        NewPath.push_back(BB);
+        NewPath.push_back(ToBB);
+        Res.push_back(NewPath);
----------------
XChy wrote:

```suggestion
        Res.push_back({BB, ToBB});
```

https://github.com/llvm/llvm-project/pull/96127