move libevent into base

base/third_party/libevent/test/bench.c

 /*
  * Copyright 2003 Niels Provos <provos@citi.umich.edu>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 168 matching lines @@
         for (i = 0; i < 25; i++) {
                 tv = run_once();
                 if (tv == NULL)
                         exit(1);
                 fprintf(stdout, "%ld\n",
                         tv->tv_sec * 1000000L + tv->tv_usec);
         }
 
         exit(0);
 }