[3.13] gh-133940: test_strftime incorrectly calculates expected week (GH-134281) (#134302)

gh-133940: test_strftime incorrectly calculates expected week (GH-134281)

Let the system determine the correct tm_wday and tm_isdst.
(cherry picked from commit e3dda8f81832008adf19906004f0cd53de95dd0b)

Co-authored-by: Gustaf <79180496+GGyll@users.noreply.github.com>