cmake: drop two stray TLS feature checks for wolfSSL

cmake: drop two stray TLS feature checks for wolfSSL

Drop check for `SSL_set0_wbio`, `SSL_CTX_set_srp_username`.

The wolfSSL backend doesn't implement these features. The checks were
wrong, and also missing from `./configure`.

If they get implemented, the feature checks should use distinct macros
from OpenSSL; they should check for the `wolfSSL_`-prefixed APIs via
wolfSSL headers; and matching checks should be added to `./configure`.

Follow-up to 781242ffa44a9f9b95b6da5ac5a1bf6372ec6257 #11967 #11964

Closes #16339