Add new effect fields to old fork

So that when comparing relative performance, we don't penalize the new
fork for using more memory.

Author: acdlite

.eslintrc.js

@@ -122,7 +122,7 @@ module.exports = {
           // Disabled because it's also used by the Hook type.
           // 'lastEffect',
         ],
-        new: ['subtreeFlags'],
+        new: [],
       },
     ],
   },

packages/react-reconciler/src/ReactFiber.old.js

@@ -145,6 +145,8 @@ function FiberNode(
 
   this.firstEffect = null;
   this.lastEffect = null;
+  this.subtreeFlags = NoFlags;
+  this.deletions = null;
 
   this.lanes = NoLanes;
   this.childLanes = NoLanes;
@@ -284,6 +286,8 @@ export function createWorkInProgress(current: Fiber, pendingProps: any): Fiber {
     workInProgress.nextEffect = null;
     workInProgress.firstEffect = null;
     workInProgress.lastEffect = null;
+    workInProgress.subtreeFlags = NoFlags;
+    workInProgress.deletions = null;
 
     if (enableProfilerTimer) {
       // We intentionally reset, rather than copy, actualDuration & actualStartTime.
@@ -372,6 +376,7 @@ export function resetWorkInProgress(workInProgress: Fiber, renderLanes: Lanes) {
     workInProgress.lanes = renderLanes;
 
     workInProgress.child = null;
+    workInProgress.subtreeFlags = NoFlags;
     workInProgress.memoizedProps = null;
     workInProgress.memoizedState = null;
     workInProgress.updateQueue = null;
@@ -392,6 +397,8 @@ export function resetWorkInProgress(workInProgress: Fiber, renderLanes: Lanes) {
     workInProgress.lanes = current.lanes;
 
     workInProgress.child = current.child;
+    workInProgress.subtreeFlags = current.subtreeFlags;
+    workInProgress.deletions = null;
     workInProgress.memoizedProps = current.memoizedProps;
     workInProgress.memoizedState = current.memoizedState;
     workInProgress.updateQueue = current.updateQueue;
@@ -814,6 +821,8 @@ export function assignFiberPropertiesInDEV(
   target.nextEffect = source.nextEffect;
   target.firstEffect = source.firstEffect;
   target.lastEffect = source.lastEffect;
+  target.subtreeFlags = source.subtreeFlags;
+  target.deletions = source.deletions;
   target.lanes = source.lanes;
   target.childLanes = source.childLanes;
   target.alternate = source.alternate;