Ignore outfile check when `-c`(check syntax only) flag is enabled.
Treat partial hook success '\n' to fix #2361 .

Now it will parse the #2361 code as:
```
module A
end
module B
end
```
instead of
```
module A
end module B
end
```
Merge pull request #2367 from take-cheeze/ignore_outfile

Ignore outfile check when `-c`(check syntax only) flag is enabled.
Add bintest for `mrbc`.
Merge pull request #2368 from take-cheeze/partial_hook_fix

Treat partial hook success '\n' to fix #2361 .
Implement String#clear
git push origin masterMerge branch 'suzukaze-add-string.clear2'
inline str_discard(); ref #2370
clear shared and nofree flags; ref #2370