Remove _NODISCARD_FRIEND workaround

[fsb4000]

Fixes #4104

I believe the workaround is not needed since CUDA 11.3.0: https://gcc.godbolt.org/z/bPh1av5f9

C:\Dev\STL\playground>type main.cpp
template<int>
struct test {
    int i;
     [[nodiscard]] friend bool operator==(const test& lhs, const test& rhs) {
        return lhs.i == rhs.i;
    }
};

int main() {
    test<1> t1{1};
    test<1> t2{1};
    t1 == t2;
}

C:\Dev\STL\playground>nvcc main.cpp
main.cpp
main.cpp(12): warning C4834: discarding return value of function with [[nodiscard]] attribute

C:\Dev\STL\playground>nvcc --version
nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2024 NVIDIA Corporation
Built on Tue_Feb_27_16:28:36_Pacific_Standard_Time_2024
Cuda compilation tools, release 12.4, V12.4.99
Build cuda_12.4.r12.4/compiler.33961263_0

I used this version Cuda 12.4.0: https://developer.download.nvidia.com/compute/cuda/12.4.0/network_installers/cuda_12.4.0_windows_network.exe

[StephanTLavavej]

Thanks for doing the archaeology to figure out exactly when this workaround became unnecessary! 😻 This change is super safe because we began requiring CUDA 11.6.0 with #2791 in VS 2022 17.4, two years ago.

[miscco]

This mirrors what we are doing in cccl

[StephanTLavavej]

I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed.

[StephanTLavavej]

Thanks for cleaning up this old workaround! 🧹 🪄 😻