Don't wrap roots in Handle just to dereference immediately.

src/runtime/runtime-i18n.cc

 // 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.
 
 
 #ifdef V8_I18N_SUPPORT
 #include "src/runtime/runtime-utils.h"
 
 #include <memory>
 
@@ skipping 908 matching lines @@
   if (!break_iterator) return isolate->ThrowIllegalOperation();
 
   // TODO(cira): Remove cast once ICU fixes base BreakIterator class.
   icu::RuleBasedBreakIterator* rule_based_iterator =
       static_cast<icu::RuleBasedBreakIterator*>(break_iterator);
   int32_t status = rule_based_iterator->getRuleStatus();
   // Keep return values in sync with JavaScript BreakType enum.
   if (status >= UBRK_WORD_NONE && status < UBRK_WORD_NONE_LIMIT) {
     return *isolate->factory()->NewStringFromStaticChars("none");
   } else if (status >= UBRK_WORD_NUMBER && status < UBRK_WORD_NUMBER_LIMIT) {
-    return *isolate->factory()->number_string();
+    return isolate->heap()->number_string();
   } else if (status >= UBRK_WORD_LETTER && status < UBRK_WORD_LETTER_LIMIT) {
     return *isolate->factory()->NewStringFromStaticChars("letter");
   } else if (status >= UBRK_WORD_KANA && status < UBRK_WORD_KANA_LIMIT) {
     return *isolate->factory()->NewStringFromStaticChars("kana");
   } else if (status >= UBRK_WORD_IDEO && status < UBRK_WORD_IDEO_LIMIT) {
     return *isolate->factory()->NewStringFromStaticChars("ideo");
   } else {
     return *isolate->factory()->NewStringFromStaticChars("unknown");
   }
 }
@@ skipping 350 matching lines @@
   Handle<FixedArray> date_cache_version =
       Handle<FixedArray>::cast(isolate->eternal_handles()->GetSingleton(
           EternalHandles::DATE_CACHE_VERSION));
   return date_cache_version->get(0);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_I18N_SUPPORT