Fix CVE-2022-3602 in punycode decoder.

An off by one error in the punycode decoder allowed for a single unsigned int
overwrite of a buffer which could cause a crash and possible code execution.

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(cherry picked from commit fe3b639dc19b325846f4f6801f2f4604f56e3de3)
