This patch was originally developed by Vladislav Vaintroub.
The main changes are:

 * Use TryEnterCriticalSection in os_fast_mutex_trylock().
 * Use lightweight condition variables on Vista or later Windows;
   but fall back to events on older Windows, such as XP.

This patch also fixes the following bugs:
  bug# 52102 InnoDB Plugin shows performance drop compared to InnoDB
             on Windows
  bug# 53204 os_fastmutex_trylock is implemented incorrectly on Windows

rb://363 approved by Inaam Rana