Repro: https://codesandbox.io/s/fast-water-4i4jb

Notice the flash. I'd expect `suspended` to be `true` during the high pri render.
const render = block._render;
  const data = block._data;
  
  let nextChildren;
  prepareToReadContext(workInProgress, renderExpirationTime);
  if (__DEV__) {
    ReactCurrentOwner.current = workInProgress;
    setIsRendering(true);
    nextChildren = renderWithHooks(
      current,
      workInProgress,
      render,
      nextProps,
      data,
      renderExpirationTime,
    );
    if (
      debugRenderPhaseSideEffectsForStrictMode &&
      workInProgress.mode & StrictMode
    ) {
      nextChildren = renderWithHooks(
        current,
        workInProgress,
        render,
        nextProps,
        data,
        renderExpirationTime,
      );
    }