[2.0 / next] An uninitialized async memo whose re-run throws from a dependency loses the error; Loading reveals an empty hole #4364

const [s, set] = createSignal(0);
let release;
const gate = new Promise(r => (release = r));
render(() => {
  const m0 = createMemo(() => { if (s() === 2) throw new Error("boom"); return s(); });
  const m1 = createMemo(() => { const v = m0() + s(); return gate.then(() => v); });
  return (
    <Errored fallback={e => `[E ${e()?.message}]`}>
      <Loading fallback="[L]"><span>{m1()}</span></Loading>
    </Errored>
  );
}, el);
flush();          // [L]
set(2); flush();  // <span></span>   — expected [E boom]
release(1);       // still <span></span>