Set return pointer of deleted tree

When deleting a host node, we follow the return path to find the
nearest mounted host parent. Which means the return pointer of the
deleted tree must be correct in the mutation phase.

Author: acdlite

packages/react-reconciler/src/ReactFiberCommitWork.new.js

@@ -1964,6 +1964,10 @@ function commitMutationEffects_begin(
     if (deletions !== null) {
       for (let i = 0; i < deletions.length; i++) {
         const childToDelete = deletions[i];
+        // When deleting a host node, we follow the return path to find the
+        // neartest mounted host parent. Which means the return pointer of
+        // the deleted tree must be correct.
+        childToDelete.return = fiber;
         if (__DEV__) {
           invokeGuardedCallback(
             null,

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

@@ -1964,6 +1964,10 @@ function commitMutationEffects_begin(
     if (deletions !== null) {
       for (let i = 0; i < deletions.length; i++) {
         const childToDelete = deletions[i];
+        // When deleting a host node, we follow the return path to find the
+        // neartest mounted host parent. Which means the return pointer of
+        // the deleted tree must be correct.
+        childToDelete.return = fiber;
         if (__DEV__) {
           invokeGuardedCallback(
             null,