Move utils.h and utils.cc from runtime/vm to runtime/platform

runtime/vm/bigint_operations.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/bigint_operations.h"
 
 #include <openssl/crypto.h>
 
+#include "platform/utils.h"
 #include "vm/bigint_store.h"
 #include "vm/double_internals.h"
 #include "vm/exceptions.h"
-#include "vm/utils.h"
 #include "vm/zone.h"
 
 namespace dart {
 
 bool Bigint::IsZero() const { return BN_is_zero(BNAddr()); }
 bool Bigint::IsNegative() const { return !!BNAddr()->neg; }
 
 
 void Bigint::SetSign(bool is_negative) const {
   BIGNUM* bn = MutableBNAddr();
@@ skipping 604 matching lines @@
   result.ToggleSign();
   return result.raw();
 }
 
 
 int BigintOperations::Compare(const Bigint& a, const Bigint& b) {
   return BN_cmp(a.BNAddr(), b.BNAddr());
 }
 
 }  // namespace dart