DevTools: Fix WebInspector.debuggerModel.debuggerPausedDetails checks in Tests.js

TBR=pfeldman

Review URL: https://codereview.chromium.org/225183004

git-svn-id: svn://svn.chromium.org/blink/trunk@170838 bbb929c8-8fbe-4397-9dbb-9b2b20218538