Remove unnecessary includes of v8 headers from platform files

src/platform-cygwin.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 24 matching lines @@
 #include <strings.h>    // index
 #include <sys/time.h>
 #include <sys/mman.h>   // mmap & munmap
 #include <unistd.h>     // sysconf
 
 #undef MAP_TYPE
 
 #include "v8.h"
 
 #include "platform.h"
-#include "simulator.h"
 #include "v8threads.h"
-#include "vm-state-inl.h"
 #include "win32-headers.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 290 matching lines @@
   return VirtualFree(base, 0, MEM_RELEASE) != 0;
 }
 
 
 bool VirtualMemory::HasLazyCommits() {
   // TODO(alph): implement for the platform.
   return false;
 }
 
 } }  // namespace v8::internal