Update acme/autocert test to not depend on whether idna.Lookup uses transitional processing (Go 1.17 and earlier) or nontransitional processing (Go 1.18 and later). Change-Id: I29ca0aaca0ac75a932919a4c7cf8e9fca033b497 Reviewed-on: https://go-review.googlesource.com/c/crypto/+/364014 Trust: Damien Neil <dneil@google.com> Reviewed-by: Ian Lance Taylor <iant@golang.org>