[parser] Allow escaped future reserved keywords as identifiers

Bug: v8:11688
Change-Id: I35cf5d11d1a9af68be29c8e00224667ddbf07e7a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2864388Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74362}

src/parsing/parser-base.h

@@ -4427,6 +4427,12 @@ bool ParserBase<Impl>::IsNextLetKeyword() {
     case Token::ASYNC:
       return true;
     case Token::FUTURE_STRICT_RESERVED_WORD:
+    case Token::ESCAPED_STRICT_RESERVED_WORD:
+      // The early error rule for future reserved keywords
+      // (ES#sec-identifiers-static-semantics-early-errors) uses the static
+      // semantics StringValue of IdentifierName, which normalizes escape
+      // sequences. So, both escaped and unescaped future reserved keywords are
+      // allowed as identifiers in sloppy mode.
       return is_sloppy(language_mode());
     default:
       return false;

test/test262/test262.status

@@ -588,15 +588,6 @@
   # https://bugs.chromium.org/p/v8/issues/detail?id=11689
   'built-ins/BigInt/wrapper-object-ordinary-toprimitive': [FAIL],
 
-  # https://bugs.chromium.org/p/v8/issues/detail?id=11688
-  'language/future-reserved-words/implements': [FAIL],
-  'language/future-reserved-words/interface': [FAIL],
-  'language/future-reserved-words/private': [FAIL],
-  'language/future-reserved-words/protected': [FAIL],
-  'language/future-reserved-words/public': [FAIL],
-  'language/future-reserved-words/package': [FAIL],
-  'language/future-reserved-words/static': [FAIL],
-
    # https://bugs.chromium.org/p/v8/issues/detail?id=11690
   'language/module-code/export-expname-binding-index': [FAIL],