openssl: add a simple smoke test for the legacy provider

[ngie]

Summary

This change adds a simple smoke test for the legacy provider to ensure
that the provider doesn't break in the future when performing updates.

This is not a functional or system test; the OpenSSL test suite does a
much better job at doing this than we can.

MFC after: 1 month

Test Plan

$ kyua test -k /usr/tests/secure/lib/libcrypto/Kyuafile 
libcrypto_test:legacy_provider  ->  passed  [0.022s]

Results file id is usr_tests_secure_lib_libcrypto.20251012-041436-984512
Results saved to /home/ngie/.kyua/store/results.usr_tests_secure_lib_libcrypto.20251012-041436-984512.db

1/1 passed (0 broken, 0 failed, 0 skipped)