bench/string: fix typo in shell script
bench/string: fix typo in shell script

Signed-off-by: Jean Privat <51f8b1fa9b424745378826727452997ee2a7c3d7@pryen.org>

jcbrinfo/nit,privat/nit,jcbrinfo/nit,privat/nit,jcbrinfo/nit,jcbrinfo/nit,privat/nit,privat/nit,jcbrinfo/nit,jcbrinfo/nit,jcbrinfo/nit,privat/nit,jcbrinfo/nit,jcbrinfo/nit,privat/nit,privat/nit,privat/nit,privat/nit,jcbrinfo/nit,jcbrinfo/nit,privat/nit