message: fix another constexpr crash
diff: @@ -1583,6 +1583,7 @@ public:
  // If there is a global variable with initializer, put them at init block.
  auto &entry_name = Fn.getFirstBB().getName();
  BB = &Fn.getBB("#init", true);
  + insert_constexpr_before = nullptr;
  // Ensure all src globals exist in target as well
  for (auto &gvname : gvnamesInSrc) {
  