crypto/x509: high-CPU VerifyHostname behavior via repeated hostname splitting [1.26 backport]

[gopherbot]

@thatnealpatel requested issue #79694 to be considered for backport to the next 1.26 minor release.

Hi @gopherbot, please open backport issues for this security issue.

[gopherbot]

Change https://go.dev/cl/783942 mentions this issue: [release-branch.go1.26] crypto/x509: split candidate hostname only once

[gopherbot]

Closed by merging CL 783942 (commit ce5a3e7) to release-branch.go1.26.