bug#65796: dynamic module non_local_exit_get overwrites exit signals

[Xinyang Chen]

Currently `module_non_local_exit_get` returns pointers to fields in emacs_env_private:

```

  if (p->pending_non_local_exit != emacs_funcall_exit_return)
    {
      *symbol = &p->non_local_exit_symbol;
      *data = "">    }

```

this means that if one tries to:

```

funcall(...);

non_local_exit_get(&s1, &d1);

funcall(...);

non_local_exit_get(&s2, &d2);

non_local_exit_signal(s1, d1);

```

you would signal the second error, instead of the first error (I expected this to happen).

It seems to me that `module_non_local_exit_get` should `allocate_emacs_value` instead.

-Alan