[esnext] implement frontend changes for async/await proposal

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index a2cc6d5b305506d441cc99cc35f0aadb4a9f40d6..4baa4a8f10cdf6f68d0eecf507cdbb034e21ff2f 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -4288,7 +4288,7 @@ class ScopeInfo : public FixedArray {
   class HasSimpleParametersField
       : public BitField<bool, AsmFunctionField::kNext, 1> {};
   class FunctionKindField
-      : public BitField<FunctionKind, HasSimpleParametersField::kNext, 8> {};
+      : public BitField<FunctionKind, HasSimpleParametersField::kNext, 9> {};
 
   // BitFields representing the encoded information for context locals in the
   // ContextLocalInfoEntries part.
@@ -7142,6 +7142,7 @@ class SharedFunctionInfo: public HeapObject {
     kIsGetterFunction,
     kIsSetterFunction,
     // byte 3
+    kIsAsyncFunction,
     kDeserialized,
     kIsDeclaration,
     kCompilerHintsCount,  // Pseudo entry
@@ -7164,7 +7165,7 @@ class SharedFunctionInfo: public HeapObject {
   ASSERT_FUNCTION_KIND_ORDER(kSetterFunction, kIsSetterFunction);
 #undef ASSERT_FUNCTION_KIND_ORDER
 
-  class FunctionKindBits : public BitField<FunctionKind, kIsArrow, 8> {};
+  class FunctionKindBits : public BitField<FunctionKind, kIsArrow, 9> {};
 
   class DeoptCountBits : public BitField<int, 0, 4> {};
   class OptReenableTriesBits : public BitField<int, 4, 18> {};