Split up [github] testers (#2560)

services/github/github-commit-activity.tester.js

services/github/github-commit-status.tester.js

services/github/github-commits-since.tester.js

services/github/github-contributors.service.js

services/github/github-contributors.tester.js

services/github/github-downloads.tester.js

services/github/github-followers.tester.js

services/github/github-forks.tester.js

services/github/github-issue-detail.tester.js

services/github/github-issues.tester.js

services/github/github-languages.tester.js

services/github/github-last-commit.tester.js

services/github/github-license.tester.js

services/github/github-release.tester.js

services/github/github-repo-size.tester.js

services/github/github-search.tester.js

services/github/github-size.tester.js

services/github/github-stars.tester.js

services/github/github-tag.tester.js

services/github/github-watchers.tester.js