Performance regression in replace.Convert.time_replace
https://github.com/pandas-dev/pandas/pull/34999 caused a 2x slowdown in replace.Convert.time_replace (https://pandas.pydata.org/speed/pandas/index.html#replace.Convert.time_replace?p-constructor=%27Series%27&p-replace_data=%27Timestamp%27&commits=dbfbef7eaea7f23a42d9a65344b5745fc055f5b4)

