Update `str_chilled_p` for Ruby 4.1 #616

Job	Run time
ruby-versions / Generate Ruby versions	5s
windows-latest 3.3	54s
windows-latest jruby-head	1m 42s
windows-latest 3.1	1m 4s
windows-latest 3.0	1m 1s
windows-latest 2.7	1m 34s
windows-latest mingw	54s
windows-latest mswin	1m 13s
windows-latest 3.4	1m 3s
windows-latest 4.0	55s
windows-latest 3.2	1m 3s
	11m 28s

Provide feedback