Remove the dependency of Zone on Isolate

test/cctest/test-liveedit.cc

 // Copyright 2007-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 77 matching lines @@
   DiffChunkStruct** next_chunk_pointer_;
   DiffChunkStruct* current_chunk_;
   Zone* zone_;
 };
 
 
 void CompareStringsOneWay(const char* s1, const char* s2,
                           int expected_diff_parameter = -1) {
   StringCompareInput input(s1, s2);
 
-  Zone zone(CcTest::i_isolate());
+  Zone zone;
 
   DiffChunkStruct* first_chunk;
   ListDiffOutputWriter writer(&first_chunk, &zone);
 
   Comparator::CalculateDifference(&input, &writer);
 
   int len1 = StrLength(s1);
   int len2 = StrLength(s2);
 
   int pos1 = 0;
@@ skipping 58 matching lines @@
   CompareStrings("cat", "cut", 2);
   CompareStrings("ct", "cut", 1);
   CompareStrings("cat", "ct", 1);
   CompareStrings("cat", "cat", 0);
   CompareStrings("", "", 0);
   CompareStrings("cat", "", 3);
   CompareStrings("a cat", "a capybara", 7);
   CompareStrings("abbabababababaaabbabababababbabbbbbbbababa",
                  "bbbbabababbbabababbbabababababbabbababa");
 }