Account for C++17 deferred temporary materialization in invocable_r

[CaseyCarter]

...and is_invocable_r_v, as required to be able to initialize std::function<non_movable_type(args...)> (see DevCom-676429). This
fixes DevCom-676429 for Clang, but not MSVC due to a guaranteed copy elision bug VSO-1026729.

[StephanTLavavej]

There are ~100 test configs failing; examples:

1: C:\a\1\s\tests\std\tests\Dev11_0535636_functional_overhaul\test.cpp(1647): error C2440: 'initializing': cannot convert from 'test_function::<lambda_8>' to 'std::function<void (std::string &,std::unique_ptr<std::string,std::default_delete<std::string>> &&,std::unique_ptr<int,std::default_delete<int>>)>'
1: C:\a\1\s\tests\std\tests\Dev11_0535636_functional_overhaul\test.cpp(1647): note: No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called

1: C:\a\1\s\tests\std\tests\VSO_0105317_expression_sfinae\test.cpp(31): error C2338: is_invocable_r_v<void, Callable, Args...>
1: C:\a\1\s\tests\std\tests\VSO_0105317_expression_sfinae\test.cpp(38): note: see reference to class template instantiation 'HasInvokeResultT<void,Callable,int>' being compiled
1:         with
1:         [
1:             Callable=FP
1:         ]
1: C:\a\1\s\tests\std\tests\VSO_0105317_expression_sfinae\test.cpp(54): note: see reference to class template instantiation 'HasResultOfT<FP (int)>' being compiled

[StephanTLavavej]

I'll push a change to fix the duplicated test lines, which look like a copy-paste relic.

[StephanTLavavej]

Thanks for salvaging my work! This looks good and your naming is better.

[mnatsuhara]

😵

[StephanTLavavej]

Thanks again for fixing this arcane machinery! 🔮