time: time zone lookup using extend string makes wrong start time for non-DST zones [1.19 backport]

[gopherbot]

@ianlancetaylor requested issue #58682 to be considered for backport to the next 1.19 minor release.

@gopherbot Please open backport issues

We incorrectly handle the timezone bounds for timezones that used to have daylight savings time and then stopped.

[gopherbot]

Change https://go.dev/cl/478657 mentions this issue: [release-branch.go1.19] time: fix timezone lookup logic for non-DST zones

[gopherbot]

Closed by merging 2adec52 to release-branch.go1.19.