This commits is a dummy implementation of file advisory locks. Specifically, for regular files, fcntl `F_SETLK` (i.e., acquiring or releasing locks) always succeeds and fcntl `F_GETLK` (i.e., testing locks) always returns no locks.
* Modify fcntl system call to support F_GETFL and F_SETFL * Separate OpenFlags to CreationsFlags, AccessMode and StatusFlags