Transfer mounted effects on suspend in legacy mode

In legacy mode, a component that suspends bails out and commit in
its previous state. If the component previously had mounted effects,
we must transfer those to the work-in-progress so they don't
get dropped.

packages/react-reconciler/src/ReactFiberThrow.js

@@ -199,9 +199,11 @@ function throwException(
       // to render it.
       let currentSource = sourceFiber.alternate;
       if (currentSource) {
+        sourceFiber.updateQueue = currentSource.updateQueue;
         sourceFiber.memoizedState = currentSource.memoizedState;
         sourceFiber.expirationTime = currentSource.expirationTime;
       } else {
+        sourceFiber.updateQueue = null;
         sourceFiber.memoizedState = null;
       }
     }