ci: Add nightly CI job for clang++ with NMake
In commit c1f4bd79 (ci: Add LLVM/Clang 13.0 nightly CI jobs on Windows, 2022-02-02) we added three of the four combinations of `clang-cl`/`clang++` with NMake/Ninja. Add the last combination.
In commit c1f4bd79 (ci: Add LLVM/Clang 13.0 nightly CI jobs on Windows, 2022-02-02) we added three of the four combinations of `clang-cl`/`clang++` with NMake/Ninja. Add the last combination.