Function nested

test/stdexec/types/test_task.cpp:258–264

  }

  auto nested() -> ex::task<int>
  {
    auto sched = co_await ex::read_env(ex::get_scheduler);
    static_assert(std::same_as<decltype(sched), ex::task_scheduler>);
    co_await ex::schedule(sched);
    co_return 42;
  }

  auto test_task_awaits_inline_sndr_without_stack_overflow() -> ex::task<int>
  {