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

Notice the flash. I'd expect `suspended` to be `true` during the high pri render.
Before entering the begin phase, clear pending update priority.
   TODO: This assumes that we're about to evaluate the component and process
   the update queue. However, there's an exception: SimpleMemoComponent
   sometimes bails out later in the begin phase. This indicates that we should
   move this assignment out of the common path and into each branch.
  workInProgress.expirationTime = NoWork;
  switch (workInProgress.tag) {
    case IndeterminateComponent: {
      return mountIndeterminateComponent(
        current,
        workInProgress,
        workInProgress.type,
        renderExpirationTime,
      );
    }
    case LazyComponent: {
      const elementType = workInProgress.elementType;
      return mountLazyComponent(
        current,
        workInProgress,
        elementType,
        updateExpirationTime,
        renderExpirationTime,
      );
    }
    case FunctionComponent: {
      const Component = workInProgress.type;
      const unresolvedProps = workInProgress.pendingProps;
      const resolvedProps =
        workInProgress.elementType === Component