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

Notice the flash. I'd expect `suspended` to be `true` during the high pri render.
} from './ReactFiber';
import {
  shouldSetTextContent,
  supportsHydration,
  canHydrateInstance,
  canHydrateTextInstance,
  canHydrateSuspenseInstance,
  getNextHydratableSibling,
  getFirstHydratableChild,
  hydrateInstance,
  hydrateTextInstance,
  hydrateSuspenseInstance,
  getNextHydratableInstanceAfterSuspenseInstance,
  didNotMatchHydratedContainerTextInstance,
  didNotMatchHydratedTextInstance,
  didNotHydrateContainerInstance,
  didNotHydrateInstance,
  didNotFindHydratableContainerInstance,
  didNotFindHydratableContainerTextInstance,
  didNotFindHydratableContainerSuspenseInstance,
  didNotFindHydratableInstance,
  didNotFindHydratableTextInstance,
  didNotFindHydratableSuspenseInstance,
} from './ReactFiberHostConfig';
import {enableSuspenseServerRenderer} from 'shared/ReactFeatureFlags';
import {Never} from './ReactFiberExpirationTime';
let hydrationParentFiber: null | Fiber = null;
let nextHydratableInstance: null | HydratableInstance = null;
let isHydrating: boolean = false;
function warnIfHydrating() {