Tests: compatibility with "openssl" app from OpenSSL 3.2.0. OpenSSL 3.2.0's "openssl" app generates X.509v3 certificates unless explicitly asked not to. Such certificates, even self-signed ones, cannot be used to sign other certificates without CA:TRUE explicitly set in the basicConstraints extension. As a result, tests doing so are now failing. Fix is to provide basicConstraints with CA:TRUE for self-signed root certificates used in "openssl ca" calls.