message: remove HAVE_VALGRIND condition
  the test no longer breaks on valgrin 3.12.0
diff: @@ -2462,9 +2462,6 @@ static void scheduleRequestAndThrowDummyException(ClientConnection::ptr conn,
  MORDOR_THROW_EXCEPTION(DummyException());
  }
  -
  -#ifndef HAVE_VALGRIND
  -// failWhileFlushOtherWaiting test case causes valgrind crash, conditionally disable it
  MORDOR_UNITTEST(HTTPClient, failWhileFlushOtherWaiting)
  {
  WorkerPool pool;
  @@ -2488,8 +2485,6 @@ MORDOR_UNITTEST(HTTPClient, failWhileFlushOtherWaiting)
  // reset onWrite callback to break the conn->testStream->conn reference cycle
  testStream->onWrite(0, 0);
  }
  -#endif
  -
  MORDOR_UNITTEST(HTTPClient, failWhileRequestingOtherWaiting)
  {
  