WIP [esnext] implement async iteration proposal

src/compiler/access-builder.cc

Index: src/compiler/access-builder.cc
diff --git a/src/compiler/access-builder.cc b/src/compiler/access-builder.cc
index 3bd63cc3d5232828caf674882964f0f29c4ba932..eac04d09637dd37c8cd399ae99f63ae119d637cb 100644
--- a/src/compiler/access-builder.cc
+++ b/src/compiler/access-builder.cc
@@ -173,6 +173,16 @@ FieldAccess AccessBuilder::ForJSGeneratorObjectInputOrDebugPos() {
 }
 
 // static
+FieldAccess AccessBuilder::ForJSAsyncGeneratorObjectAwaitInput() {
+  FieldAccess access = {
+      kTaggedBase,         JSAsyncGeneratorObject::kAwaitInputOffset,
+      Handle<Name>(),      MaybeHandle<Map>(),
+      Type::NonInternal(), MachineType::AnyTagged(),
+      kFullWriteBarrier};
+  return access;
+}
+
+// static
 FieldAccess AccessBuilder::ForJSGeneratorObjectRegisterFile() {
   FieldAccess access = {
       kTaggedBase,         JSGeneratorObject::kRegisterFileOffset,