message: [test] Remove randomness
  This particular test fails once every so many runs on GreenDragon. Given
  that the randomness in the inferior isn't critical to the test, I
  removed it in the hopes that it is the cause of the flakiness.
diff: #include <chrono>
  #include <condition_variable>
  #include <cstdio>
  -#include <random>
  #include <thread>
  -std::default_random_engine g_random_engine{std::random_device{}()};
  -std::uniform_int_distribution<> g_distribution{0, 3000000};
  std::condition_variable g_condition_variable;
  std::mutex g_mutex;
  int g_count;
  @@ -74,17 +71,15 @@ thread_func (uint32_t thread_index)
  uint32_t val;
  while (count++ < 15)
  {
  - // random micro second sleep from zero to 3 seconds
  - int usec = g_distribution(g_random_engine);
  - printf ("%s (thread = %u) doing a usleep (%d)...\n", __FUNCTION__, thread_index, usec);
  - std::this_thread::sleep_for(std::chrono::microseconds{usec});
  + printf ("%s (thread = %u) sleeping for 1 second...\n", __FUNCTION__, thread_index);
  + std::this_thread::sleep_for(std::chrono::seconds(1));
  if (count < 7)
  val = access_pool ();
  else
  val = access_pool (true);
  - printf ("%s (thread = %u) after usleep access_pool returns %d (count=%d)...\n", __FUNCTION__, thread_index, val, count);
  + printf ("%s (thread = %u) after sleep access_pool returns %d (count=%d)...\n", __FUNCTION__, thread_index, val, count);
  }
  printf ("%s (thread index = %u) exiting...\n", __FUNCTION__, thread_index);
  }
  