[parser] Enforce module-specific identifier restriction

src/parsing/preparser.h

Index: src/parsing/preparser.h
diff --git a/src/parsing/preparser.h b/src/parsing/preparser.h
index 253251c0734620ab3279cae4897e77cc0afcdfb7..39f363a22907da15c18aa54b98673a7d380f7b81 100644
--- a/src/parsing/preparser.h
+++ b/src/parsing/preparser.h
@@ -55,6 +55,12 @@ class PreParserIdentifier {
   static PreParserIdentifier Constructor() {
     return PreParserIdentifier(kConstructorIdentifier);
   }
+  static PreParserIdentifier Enum() {
+    return PreParserIdentifier(kEnumIdentifier);
+  }
+  static PreParserIdentifier Await() {
+    return PreParserIdentifier(kAwaitIdentifier);
+  }
   bool IsEval() const { return type_ == kEvalIdentifier; }
   bool IsArguments() const { return type_ == kArgumentsIdentifier; }
   bool IsEvalOrArguments() const { return IsEval() || IsArguments(); }
@@ -64,7 +70,8 @@ class PreParserIdentifier {
   bool IsYield() const { return type_ == kYieldIdentifier; }
   bool IsPrototype() const { return type_ == kPrototypeIdentifier; }
   bool IsConstructor() const { return type_ == kConstructorIdentifier; }
-  bool IsFutureReserved() const { return type_ == kFutureReservedIdentifier; }
+  bool IsEnum() const { return type_ == kEnumIdentifier; }
+  bool IsAwait() const { return type_ == kAwaitIdentifier; }
   bool IsFutureStrictReserved() const {
     return type_ == kFutureStrictReservedIdentifier ||
            type_ == kLetIdentifier || type_ == kStaticIdentifier ||
@@ -91,7 +98,9 @@ class PreParserIdentifier {
     kArgumentsIdentifier,
     kUndefinedIdentifier,
     kPrototypeIdentifier,
-    kConstructorIdentifier
+    kConstructorIdentifier,
+    kEnumIdentifier,
+    kAwaitIdentifier
   };
 
   explicit PreParserIdentifier(Type type) : type_(type) {}