Remove legacy API on Utf16CharacterStream.

src/parsing/parser-base.h

Index: src/parsing/parser-base.h
diff --git a/src/parsing/parser-base.h b/src/parsing/parser-base.h
index fad093081187054b9b15764ef4b48cf8907e7581..8640d1f36026dc41e75567ca602f57e574559f08 100644
--- a/src/parsing/parser-base.h
+++ b/src/parsing/parser-base.h
@@ -3869,9 +3869,9 @@ ParserBase<Impl>::ParseArrowFunctionLiteral(
                                formal_parameters.scope->AllowsLazyParsing());
       if (is_lazily_parsed) {
         Scanner::BookmarkScope bookmark(scanner());
-        bool may_abort = bookmark.Set();
+        bookmark.Set();
         LazyParsingResult result = impl()->SkipLazyFunctionBody(
-            &materialized_literal_count, &expected_property_count, may_abort,
+            &materialized_literal_count, &expected_property_count, true,
             CHECK_OK);
 
         if (formal_parameters.materialized_literals_count > 0) {