[builtins] Introduce new TFC macro and auto-generate TFS descriptors

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

 // Copyright 2017 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/builtins/builtins-async-gen.h"
 #include "src/builtins/builtins-utils-gen.h"
 #include "src/builtins/builtins.h"
 #include "src/code-factory.h"
 #include "src/code-stub-assembler.h"
 #include "src/frames-inl.h"
@@ skipping 514 matching lines @@
     CallStub(CodeFactory::ResumeGenerator(isolate()), context,
              LoadValueFromAsyncGeneratorRequest(next), generator, resume_type,
              SmiConstant(static_cast<int>(SuspendFlags::kAsyncGeneratorYield)));
     var_state.Bind(LoadGeneratorState(generator));
     var_next.Bind(LoadFirstAsyncGeneratorRequestFromQueue(generator));
     Goto(&start);
   }
 }
 
 TF_BUILTIN(AsyncGeneratorResolve, AsyncGeneratorBuiltinsAssembler) {
-  typedef AsyncGeneratorResolveDescriptor Descriptor;
   Node* const generator = Parameter(Descriptor::kGenerator);
   Node* const value = Parameter(Descriptor::kValue);
   Node* const done = Parameter(Descriptor::kDone);
   Node* const context = Parameter(Descriptor::kContext);
 
   Node* const next = TakeFirstAsyncGeneratorRequestFromQueue(generator);
   Node* const promise = LoadPromiseFromAsyncGeneratorRequest(next);
 
   Node* const wrapper = AllocateAndInitJSPromise(context);
   CallBuiltin(Builtins::kResolveNativePromise, context, wrapper, value);
@@ skipping 15 matching lines @@
 
   Node* const next = TakeFirstAsyncGeneratorRequestFromQueue(generator);
   Node* const promise = LoadPromiseFromAsyncGeneratorRequest(next);
 
   Return(CallBuiltin(Builtins::kRejectNativePromise, context, promise, value,
                      TrueConstant()));
 }
 
 }  // namespace internal
 }  // namespace v8