interp: make 'wc` in test scripts portable
interp: make 'wc` in test scripts portable

wc in mac prints a trailing whitspace before its output:
```
$ echo "foo" > a; wc -c <a
       4
```

we can use either `sed`, `tr` or `xargs` - i used `tr` since `sed`
is a bit complicated to type and `xargs` adds `\r` character on windows

for some cases i used `-d` because we don't want need any `:space:`
character at all while in some i use `-s` to at least squeeze `:space:`
character and make it predictable

mvdan/sh,mvdan/sh,mvdan/sh,mvdan/sh