Don't explicitly tear down code range in cctest/test-alloc/CodeRange to avoid double-free.

test/cctest/test-alloc.cc

 // Copyright 2012 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 225 matching lines @@
       int index = Pseudorandom() % blocks.length();
       code_range.FreeRawMemory(blocks[index].base, blocks[index].size);
       current_allocated -= blocks[index].size;
       if (index < blocks.length() - 1) {
         blocks[index] = blocks.RemoveLast();
       } else {
         blocks.RemoveLast();
       }
     }
   }
-
-  code_range.TearDown();
 }