valueOf offset calculate not correctly, when crossing summertime

**Describe the bug**
valueOf offset calculate not correctly, when crossing summertime, it subtract one more hour

**Expected behavior**
valueOf should be correct

**Information**
- Day.js Version v1.10.8
- system timezone Europe/Warsaw
- system date 2022-03-01
- dayjs.tz.setDefault('Europe/Warsaw')
- dayjs.tz().endOf('month').valueOf() -> 1648760399999, it should be 1648763999999

Reproduce the issue with Day.js v1.10.8 using the Europe/Warsaw timezone, dayjs.tz.setDefault('Europe/Warsaw'), and dayjs.tz().endOf('month').valueOf(). Trace the timezone and end-of-month calculation from that entry point; done means the result is 1648763999999 rather than 1648760399999 when crossing summertime.

Written by the indexing model from the issue text.