Remove support for calling getrandom(), we now always call getentropy()
Remove support for calling getrandom(), we now always call getentropy()

Only Linux and FreeBSD provide getrandom(), but they both also provide
getentropy() since the same version and we already tried to call that.

Reviewed-by: Andy Polyakov <015edf36635e030d5e009e08808a59984e629740@openssl.org>
GH: #6405

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl