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

runtime/vm/assert.cc

-// Copyright (c) 2011, 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 <cstdlib>
-#include <sstream>
-#include <string>
-
-#include "vm/assert.h"
-
-namespace dart {
-
-// Exit with a failure code when we miss an EXPECT check.
-static void failed_exit(void) {
-  exit(255);
-}
-
-void DynamicAssertionHelper::Fail(const char* format, ...) {
-  std::stringstream stream;
-  stream << file_ << ":" << line_ << ": error: ";
-
-  va_list arguments;
-  va_start(arguments, format);
-  char buffer[KB];
-  vsnprintf(buffer, sizeof(buffer), format, arguments);
-  va_end(arguments);
-  stream << buffer << std::endl;
-
-  // Get the message from the string stream and dump it on stderr.
-  std::string message = stream.str();
-  fprintf(stderr, "%s", message.c_str());
-
-  // In case of failed assertions, abort right away. Otherwise, wait
-  // until the program is exiting before producing a non-zero exit
-  // code through abort.
-  // TODO(5411324): replace std::abort with OS::Abort so that we can handle
-  // restoring of signal handlers before aborting.
-  if (kind_ == ASSERT) {
-    std::abort();
-  }
-  static bool failed = false;
-  if (!failed) {
-    std::atexit(&failed_exit);
-  }
-  failed = true;
-}
-
-}  // namespace dart