Fix a -Wsign-compare error under GCC 4.9.2.

test/cctest/test-api.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 21011 matching lines @@
   v8::ScriptOrigin origin(v8_str("http://foo.com"));
   char* full_source = TestSourceStream::FullSourceString(chunks);
 
   EnableDebugger();
 
   v8::Handle<Script> script = v8::ScriptCompiler::Compile(
       isolate, &source, v8_str(full_source), origin);
 
   Maybe<uint32_t> result =
       script->Run(env.local()).ToLocalChecked()->Uint32Value(env.local());
-  CHECK_EQ(3, result.FromMaybe(0));
+  CHECK_EQ(3U, result.FromMaybe(0));
 
   delete[] full_source;
 
   DisableDebugger();
 }
 
 
 TEST(StreamingScriptWithInvalidUtf8) {
   // Regression test for a crash: test that invalid UTF-8 bytes in the end of a
   // chunk don't produce a crash.
@@ skipping 884 matching lines @@
 
   v8::TryCatch try_catch(CcTest::isolate());
   timeout_thread.Start();
 
   CompileRun(
       "var ab = new SharedArrayBuffer(4);"
       "var i32a = new Int32Array(ab);"
       "Atomics.futexWait(i32a, 0, 0);");
   CHECK(try_catch.HasTerminated());
 }