Fix the logic that depends on optional copy elision (#402)

* Fix the behavior when copy elision is disabled

* Update test/tbb/test_task_arena.cpp

* Rework doctest ContextScope destruction to fix MSVC compilation

* Remove raii_guard assignment + remove std::move from doctest

* Fix typo

* Rework the fix for doctest to get rid of hangs on Windows

* Add static assertion to check constructors noexcept state

* Remove copy elision disabling flag

* Add a comment with the reason of absence of std::move

Co-authored-by: Kochin, Ivan <ivan.kochin@intel.com>