Move assert.h/assert.cc from runtime/vm to runtime/platform

runtime/vm/random.cc

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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/random.h"
 
-#include "vm/assert.h"
+#include "platform/assert.h"
 #include "vm/isolate.h"
 
 namespace dart {
 
 // LSFR step with a period of 31-bits.
 // Based on http://en.wikipedia.org/wiki/Linear_feedback_shift_register
 static int32_t LinearFeedbackShiftRegisterStep(int32_t seed) {
   return (seed >> 1) ^ ((-(seed & 1)) & (1 << 30 | 1 << 27));
 }
 
 
 int32_t Random::RandomInt32() {
   Isolate* isolate = Isolate::Current();
   ASSERT(isolate != NULL);
   int32_t result = isolate->random_seed();
   int32_t new_random_seed = LinearFeedbackShiftRegisterStep(result);
   isolate->set_random_seed(new_random_seed);
   return result;
 }
 
 }  // namespace dart