tools: align the jslint summary like the test runner

Checklist

• tests and code linting passes
• the commit message follows commit guidelines

Affected core subsystem(s)

tools

Description of change

Now looks like

/usr/bin/python tools/test.py --mode=release -J \
        addon doctool known_issues message parallel sequential
[01:03|% 100|+ 1130|-   0]: Done                                               
/Applications/Xcode.app/Contents/Developer/usr/bin/make lint
./node tools/jslint.js -J benchmark lib src test tools/doc \
      tools/eslint-rules tools/jslint.js
[00:06|% 100|+ 1590|-   0]: Done 

@mscdex