Remove invalid assert

runtime/bin/eventhandler_win.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 <process.h>
 #include <winsock2.h>
 #include <ws2tcpip.h>
 #include <mswsock.h>
 
 #include "bin/builtin.h"
@@ skipping 283 matching lines @@
   event_handler_->HandleClosed(this);
   IOBuffer::DisposeBuffer(buffer);
   return false;
 }
 
 
 void FileHandle::EnsureInitialized(EventHandlerImplementation* event_handler) {
   ScopedLock lock(this);
   event_handler_ = event_handler;
   if (SupportsOverlappedIO() && completion_port_ == INVALID_HANDLE_VALUE) {
-    ASSERT(event_handler_ == NULL);
     CreateCompletionPort(event_handler_->completion_port());
   }
 }
 
 
 bool FileHandle::IsClosed() {
   return false;
 }
 
 
@@ skipping 568 matching lines @@
       _beginthreadex(NULL, 32 * 1024, EventHandlerThread, this, 0, &tid);
   if (thread_handle == -1) {
     FATAL("Failed to start event handler thread");
   }
 
   // Initialize Winsock32
   if (!Socket::Initialize()) {
     FATAL("Failed to initialized Windows sockets");
   }
 }