tests/std: Also test the latest version of CUDA

#639 was resolved by #1519 and #1539 adding test coverage for CUDA 10.1 Update 2. #1544 made this our minimum required version:

https://github.com/microsoft/STL/blob/721e3ad8952fce3447916ecdbff3863043686fa1/stl/inc/yvals_core.h#L509-L514

As of 2021-01-29, the latest version of CUDA is 11.2, see: https://developer.nvidia.com/cuda-downloads

We need to continue testing CUDA 10.1 Update 2 until we decide to increase our minimum required version. However, we should additionally be testing the latest version side-by-side. (Especially because CUDA 11 added support for C++17, see: https://news.developer.nvidia.com/cuda-11-toolkit/ )

This will involve changing our Virtual Machine Scale Set script to install the old and new CUDA versions side-by-side, and changing our test to invoke the different versions; at this time I don't know exactly what those changes will look like. Existing code:

https://github.com/microsoft/STL/blob/721e3ad8952fce3447916ecdbff3863043686fa1/azure-devops/provision-image.ps1#L147-L153
https://github.com/microsoft/STL/blob/721e3ad8952fce3447916ecdbff3863043686fa1/azure-devops/provision-image.ps1#L301-L338
https://github.com/microsoft/STL/blob/721e3ad8952fce3447916ecdbff3863043686fa1/azure-devops/provision-image.ps1#L379
https://github.com/microsoft/STL/blob/721e3ad8952fce3447916ecdbff3863043686fa1/tests/std/tests/GH_000639_nvcc_include_all/env.lst#L4

Start with azure-devops/provision-image.ps1 at the referenced CUDA installation and VM image sections, then inspect tests/std/tests/GH_000639_nvcc_include_all/env.lst. Determine how the existing CUDA 10.1 Update 2 setup is installed and invoked, then make the image support both versions and run the CUDA test with each; done means both versions are tested side-by-side.