Avoid the `curl.exe` wrapper binary created by libtool, and run the real
`curl.exe` directly for tests and version information.
This solution was used in Azure jobs. I missed it when migrating jobs
to GHA.
Applies to tests run in the `mingw, AM x86_64 c-ares U` job, which has
seen unexplained flakiness.
Ref: 354afc891d#6049
Follow-up to e53523fef0#14859Closes#15437