[esnext] prototype runtime implementation for async functions

src/bailout-reason.h

 // Copyright 2014 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_BAILOUT_REASON_H_
 #define V8_BAILOUT_REASON_H_
 
 namespace v8 {
 namespace internal {
 
@@ skipping 10 matching lines @@
   V(kArrayBoilerplateCreationFailed, "Array boilerplate creation failed")      \
   V(kArrayIndexConstantValueTooBig, "Array index constant value too big")      \
   V(kAssignmentToArguments, "Assignment to arguments")                         \
   V(kAssignmentToLetVariableBeforeInitialization,                              \
     "Assignment to let variable before initialization")                        \
   V(kAssignmentToLOOKUPVariable, "Assignment to LOOKUP variable")              \
   V(kAssignmentToParameterFunctionUsesArgumentsObject,                         \
     "Assignment to parameter, function uses arguments object")                 \
   V(kAssignmentToParameterInArgumentsObject,                                   \
     "Assignment to parameter in arguments object")                             \
+  V(kAsyncFunctionBailout, "AsyncFunction")                                    \
   V(kBadValueContextForArgumentsObjectValue,                                   \
     "Bad value context for arguments object value")                            \
   V(kBadValueContextForArgumentsValue,                                         \
     "Bad value context for arguments value")                                   \
   V(kBailedOutDueToDependencyChange, "Bailed out due to dependency change")    \
   V(kBailoutWasNotPrepared, "Bailout was not prepared")                        \
   V(kBothRegistersWereSmisInSelectNonSmi,                                      \
     "Both registers were smis in SelectNonSmi")                                \
   V(kClassLiteral, "Class literal")                                            \
   V(kCodeGenerationFailed, "Code generation failed")                           \
@@ skipping 237 matching lines @@
 };
 #undef ERROR_MESSAGES_CONSTANTS
 
 
 const char* GetBailoutReason(BailoutReason reason);
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_BAILOUT_REASON_H_