We don't actually use this anywhere, so let's remove it.

https://github.com/facebook/react/blob/f1d00156df5453bc62bd5668fefdcac4ca67e90e/src/renderers/shared/fiber/ReactFiberScheduler.js#L1504-L1512
} else {
            returnFiber.firstEffect = workInProgress;
          }
          returnFiber.lastEffect = workInProgress;
        }
      }
      if (__DEV__) {
        stopWorkTimer(workInProgress);
      }
      if (__DEV__ && ReactFiberInstrumentation.debugTool) {
        ReactFiberInstrumentation.debugTool.onCompleteWork(workInProgress);
      }
      if (siblingFiber !== null) {
        
        return siblingFiber;
      } else if (returnFiber !== null) {
        
        workInProgress = returnFiber;
        continue;
      } else {
        
        
        
        pendingCommit = workInProgress;
        return null;
      }
    }