Fix ASAN warning.

test/cctest/test-utils.cc

 // Copyright 2011 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 95 matching lines @@
     unsigned char data = buffer[index];
     data = TwoBits::encode(data, i, i % 4);
     buffer[index] = data;
   }
 
   for (int i = 0; i < words; i++) {
     const int index = TwoBits::index(offset, i);
     unsigned char data = buffer[index];
     CHECK_EQ(i % 4, TwoBits::decode(data, i));
   }
+  buffer.Dispose();
 }
 
 
 TEST(SNPrintF) {
   // Make sure that strings that are truncated because of too small
   // buffers are zero-terminated anyway.
   const char* s = "the quick lazy .... oh forget it!";
   int length = StrLength(s);
   for (int i = 1; i < length * 2; i++) {
     static const char kMarker = static_cast<char>(42);
@@ skipping 161 matching lines @@
   vec.push_back(66);
   for (auto& i : vec) {
     ++i;
   }
   int j = 12;
   for (auto i : vec) {
     CHECK_EQ(j, i);
     j += 11;
   }
 }