Fix iterator invalidation when reopting functions

Summary:
Advance the iterator before `reoptFunc()` erase the current function from the set, avoiding invalid iteration.
https://github.com/greg7mdp/parallel-hashmap?tab=readme-ov-file#iterator-invalidation-for-hash-containers

Reviewed By: alexmalyshev

Differential Revision: D97437765

fbshipit-source-id: a7cf22e082a7e798d997bd75dc5d2aa961592c12

Author: yoney

cinderx/Jit/pyjit.cpp

@@ -1375,7 +1375,12 @@ bool enable_jit_impl() {
   }
 
   size_t count = 0;
-  for (BorrowedRef<PyFunctionObject> func : jitCtx()->deoptedFuncs()) {
+  auto& funcs = jitCtx()->deoptedFuncs();
+  for (auto it = funcs.begin(); it != funcs.end();) {
+    BorrowedRef<PyFunctionObject> func = *it;
+    // Advance before reoptFunc() which erases func from funcs,
+    // invalidating the iterator pointing to it.
+    ++it;
     reoptFunc(func);
     count++;
   }