transport/tcp: ipmap tests: remove tests that cover CIDR normalization
transport/tcp: ipmap tests: remove tests that cover CIDR normalization

They broke on Go 1.17.
See
https://www.bleepingcomputer.com/news/security/go-rust-net-library-affected-by-critical-ip-address-validation-vulnerability/
for context.

fixes #514

zrepl/zrepl,zrepl/zrepl