Add AsyncIterator to well-known symbols.

Bug: chromium:872465
Cq-Include-Trybots: luci.chromium.try:linux_chromium_rel_ng
Change-Id: I75eccab304405569b40c5dcc18177354372a02c9
Reviewed-on: https://chromium-review.googlesource.com/1199464Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Marijn Kruisselbrink <mek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55563}

include/v8.h

@@ -3041,6 +3041,7 @@ class V8_EXPORT Symbol : public Name {
   static Local<Symbol> ForApi(Isolate *isolate, Local<String> name);
 
   // Well-known symbols
+  static Local<Symbol> GetAsyncIterator(Isolate* isolate);
   static Local<Symbol> GetHasInstance(Isolate* isolate);
   static Local<Symbol> GetIsConcatSpreadable(Isolate* isolate);
   static Local<Symbol> GetIterator(Isolate* isolate);

src/api.cc

@@ -7832,6 +7832,7 @@ Local<Symbol> v8::Symbol::ForApi(Isolate* isolate, Local<String> name) {
 }
 
 #define WELL_KNOWN_SYMBOLS(V)                 \
+  V(AsyncIterator, async_iterator)            \
   V(HasInstance, has_instance)                \
   V(IsConcatSpreadable, is_concat_spreadable) \
   V(Iterator, iterator)                       \