Fix string parsing tests
Fix string parsing tests

The tests were wrong because the |string| rule is not used to parse
literals but rule names.

wwall/pegjs-fn,GerHobbelt/pegjs,crguezl/pegjs,luisvt/pegjs,jlturner/pegjs,crguezl/pegjs,GerHobbelt/pegjs,jlturner/pegjs,Mingun/pegjs,Sciumo/pegjs,mcanthony/pegjs,mcanthony/pegjs,Mingun/pegjs,pegjs/pegjs,luisvt/pegjs,wwall/pegjs-fn,Sciumo/pegjs,pegjs/pegjs