vswhere needs the -products switch when building with Visual Studio Build tools. See https://developercommunity.visualstudio.com/t/vswhere-does-not-find-build-tools-for-visual-studi/703424.
Created attachment 453272 [details] patch
Committed r290614 (247887@main): <https://commits.webkit.org/247887@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 453272 [details].
<rdar://problem/89579480>