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

src/regexp/jsregexp.cc

 // Copyright 2012 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.
 
 #include "src/regexp/jsregexp.h"
 
 #include <memory>
 
 #include "src/base/platform/platform.h"
 #include "src/compilation-cache.h"
@@ skipping 6848 matching lines @@
   // If the array is a reasonably short list of substrings, convert it into a
   // list of internalized strings.
   if (type == STRING_SPLIT_SUBSTRINGS && value_array->length() < 100) {
     for (int i = 0; i < value_array->length(); i++) {
       Handle<String> str(String::cast(value_array->get(i)), isolate);
       Handle<String> internalized_str = factory->InternalizeString(str);
       value_array->set(i, *internalized_str);
     }
   }
   // Convert backing store to a copy-on-write array.
-  value_array->set_map_no_write_barrier(*factory->fixed_cow_array_map());
+  value_array->set_map_no_write_barrier(isolate->heap()->fixed_cow_array_map());
 }
 
 
 void RegExpResultsCache::Clear(FixedArray* cache) {
   for (int i = 0; i < kRegExpResultsCacheSize; i++) {
     cache->set(i, Smi::kZero);
   }
 }
 
 }  // namespace internal
 }  // namespace v8