Specifically `An update to * inside a test was not wrapped in act(...)` is not logged when a prior update threw. 

<details>
<summary>failing test (#21766)</summary>

```js
// @gate __DEV__
it('warns if a setState is called outside of act(...) after a component threw', () => {
  let setValue = null;
  function App({defaultValue}) {
    if (defaultValue === undefined) {
      throw new Error();
    }
    const [value, _setValue] = React.useState(defaultValue);
    setValue = _setValue;
    return value;
  }

  expect(() => {
    act(() => {
      render(<App defaultValue={undefined} />, container);
    });
  }).toThrow();

  act(() => {
    rerender(<App defaultValue={0} />, container);
  });

  expect(() => setValue(1)).toErrorDev([
    'An update to App inside a test was not wrapped in act(...).',
  ]);
});
```
</details>

What I noticed is that in https://github.com/facebook/react/blob/27c9c95e23ddedb9163373950e364dd62038f6c0/packages/react-reconciler/src/ReactFiberWorkLoop.new.js#L2855-L2865
the `executionContext` will still equal `RetryAfterError` when we would expect a "missing act" warning.

"missing act" warnings are working as expected with legacy roots.
if (lanes === NoLanes) {
     
    return null;
  }
   We disable time-slicing in some cases: if the work has been CPU-bound
   for too long ("expired" work, to prevent starvation), or we're in
   sync-updates-by-default mode.
   TODO: We only check `didTimeout` defensively, to account for a Scheduler
   bug we're still investigating. Once the bug in Scheduler is fixed,
   we can remove this, since we track expiration ourselves.
  let exitStatus =
    shouldTimeSlice(root, lanes) &&
    (disableSchedulerTimeoutInWorkLoop || !didTimeout)
      ? renderRootConcurrent(root, lanes)
      : renderRootSync(root, lanes);
  if (exitStatus !== RootIncomplete) {
    if (exitStatus === RootErrored) {
      executionContext |= RetryAfterError;
       
       
      if (root.hydrate) {
        root.hydrate = false;
        if (__DEV__) {
          errorHydratingContainer(root.containerInfo);
        }
        clearContainer(root.containerInfo);
      }