busybox

sort: fix -s. Closes 10671

function                                             old     new   delta
sort_main                                            786     862     +76
compare_keys                                         720     794     +74
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(add/remove: 0/0 grow/shrink: 2/0 up/down: 150/0)             Total: 150 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>