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

runtime/vm/utils_test.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 "platform/assert.h"
+#include "platform/utils.h"
 #include "vm/unit_test.h"
-#include "vm/utils.h"
 
 namespace dart {
 
 UNIT_TEST_CASE(Minimum) {
   EXPECT_EQ(0, Utils::Minimum(0, 1));
   EXPECT_EQ(0, Utils::Minimum(1, 0));
 
   EXPECT_EQ(1, Utils::Minimum(1, 2));
   EXPECT_EQ(1, Utils::Minimum(2, 1));
 
@@ skipping 143 matching lines @@
 
 UNIT_TEST_CASE(LowBits) {
   EXPECT_EQ(0xff00, Utils::Low16Bits(0xffff00));
   EXPECT_EQ(0xff, Utils::High16Bits(0xffff00));
   EXPECT_EQ(0xff00, Utils::Low32Bits(0xff0000ff00LL));
   EXPECT_EQ(0xff, Utils::High32Bits(0xff0000ff00LL));
   EXPECT_EQ(0x00ff0000ff00LL, Utils::LowHighTo64Bits(0xff00, 0x00ff));
 }
 
 }  // namespace dart