[esnext] prototype runtime implementation for async functions

src/code-stubs.h

 // Copyright 2012 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.
 
 #ifndef V8_CODE_STUBS_H_
 #define V8_CODE_STUBS_H_
 
 #include "src/allocation.h"
 #include "src/assembler.h"
 #include "src/code-stub-assembler.h"
@@ skipping 1005 matching lines @@
     return LanguageModeBits::decode(sub_minor_key());
   }
 
   FunctionKind kind() const {
     return FunctionKindBits::decode(sub_minor_key());
   }
 
  private:
   STATIC_ASSERT(LANGUAGE_END == 3);
   class LanguageModeBits : public BitField<LanguageMode, 0, 2> {};
-  class FunctionKindBits : public BitField<FunctionKind, 2, 8> {};
+  class FunctionKindBits : public BitField<FunctionKind, 2, 9> {};
 
   DEFINE_CALL_INTERFACE_DESCRIPTOR(FastNewClosure);
   DEFINE_HYDROGEN_CODE_STUB(FastNewClosure, HydrogenCodeStub);
 };
 
 
 class FastNewContextStub final : public HydrogenCodeStub {
  public:
   static const int kMaximumSlots = 64;
 
@@ skipping 2209 matching lines @@
 #undef DEFINE_HYDROGEN_CODE_STUB
 #undef DEFINE_CODE_STUB
 #undef DEFINE_CODE_STUB_BASE
 
 extern Representation RepresentationFromType(Type* type);
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CODE_STUBS_H_