Chapter 11: std::barrier requires a completion function not to throw an exception

[puhach]

Building chapter 11 fails with the following errors on MSVC 2019:

1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30037\include\barrier(76,13): error C2338: N4861 [thread.barrier.class]/5: is_nothrow_invocable_v<CompletionFunction&> shall be true
1>C:\temp\Cpp-High-Performance-Second-Edition-master\Chapter11\barriers.cpp(38): message : see reference to class template instantiation 'std::barrier<Barriers_ForkJoin_Test::TestBody::<lambda_1>>' being compiled
1>Done building project "Chapter11-Concurrency.vcxproj" -- FAILED.

This is due to the check_result function not being declared noexcept:

  auto check_result = [&] { // Completion function
    ++n_turns;
    auto is_six = [](auto i) { return i == 6; };
    done = std::all_of(dice.begin(), dice.end(), is_six);
  };
  auto bar = std::barrier{n, check_result};

To fix the issue, change it to auto check_result = [&] () noexcept { ... }.