Check for null or undefined when getting methods in AsyncFromSyncIterator

Both the .return and .throw methods are delegated to the underlying sync
iterator. These methods are retrieved using GetMethod [1], which checks
for either null or undefined instead of only undefined.

[1] https://tc39.es/ecma262/#sec-getmethod

Bug: v8:10395
Change-Id: Ide8db4270d48783da6fd1d45a5b01f2858e2828c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2258667
Auto-Submit: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68493}

src/builtins/builtins-async-iterator-gen.cc

@@ -127,7 +127,7 @@ void AsyncFromSyncBuiltinsAssembler::Generate_AsyncFromSyncIteratorMethod(
   if (if_method_undefined) {
     Label if_isnotundefined(this);
 
-    GotoIfNot(IsUndefined(method), &if_isnotundefined);
+    GotoIfNot(IsNullOrUndefined(method), &if_isnotundefined);
     if_method_undefined(native_context, promise, &reject_promise);
 
     BIND(&if_isnotundefined);

test/test262/test262.status

@@ -536,10 +536,6 @@
   # https://bugs.chromium.org/p/v8/issues/detail?id=10383
   'built-ins/RegExp/prototype/Symbol.replace/fn-invoke-args-empty-result': [FAIL],
 
-  # https://bugs.chromium.org/p/v8/issues/detail?id=10395
-  'built-ins/AsyncFromSyncIteratorPrototype/return/return-null': [FAIL],
-  'built-ins/AsyncFromSyncIteratorPrototype/throw/throw-null': [FAIL],
-
   # http://crbug/v8/10449
   'built-ins/Atomics/waitAsync/bad-range': [FAIL],
   'built-ins/Atomics/waitAsync/bigint/bad-range': [FAIL],