Drop unused v8threads include from platform files

src/platform-openbsd.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Platform-specific code for OpenBSD and NetBSD goes here. For the
 // POSIX-compatible parts, the implementation is in platform-posix.cc.
 
 #include <pthread.h>
 #include <semaphore.h>
 #include <signal.h>
@@ skipping 10 matching lines @@
 #include <unistd.h>     // sysconf
 #include <strings.h>    // index
 #include <errno.h>
 #include <stdarg.h>
 
 #undef MAP_TYPE
 
 #include "src/v8.h"
 
 #include "src/platform.h"
-#include "src/v8threads.h"
 
 
 namespace v8 {
 namespace internal {
 
 
 const char* OS::LocalTimezone(double time, TimezoneCache* cache) {
   if (std::isnan(time)) return "";
   time_t tv = static_cast<time_t>(std::floor(time/msPerSecond));
   struct tm* t = localtime(&tv);
@@ skipping 289 matching lines @@
   return munmap(base, size) == 0;
 }
 
 
 bool VirtualMemory::HasLazyCommits() {
   // TODO(alph): implement for the platform.
   return false;
 }
 
 } }  // namespace v8::internal