Add `--output-sha1` option

Instead of an full standard output file, two SHA1s can be used by
the standard checker:

- sha1 of chompped standard output
- sha1 of standard output with blank chars removed

For example, the standard output is "-1\n7\n":

- sha1 of "-1\n7": 7b80e651613b8ee99d6f2a578062673a7e40bb65
- sha1 of "-17":   6b979d97a529a16aced6c9cc59375fa4fe3962e7

`--output-sha1 7b80e651613b8ee99d6f2a578062673a7e40bb65,\
6b979d97a529a16aced6c9cc59375fa4fe3962e7` can be used to replace
`--output path-to-standard-output-file`.