Fix *some* of the remaining linting issues in `test/resources/reftest-analyzer.js`
Fix *some* of the remaining linting issues in `test/resources/reftest-analyzer.js`

Given that issue 13862 tracks updating/modernizing the code, this patch purposely limits the scope of the changes. In particular, the following things are still left to address:
 - The ESLint `no-undef` errors; for now the rule is simply disabled globally in this file.
 - A couple of unused variables are commented out for now, but could perhaps just be removed.

showpad/mozilla-pdf.js,Shoobx/pdf.js,xavier114fch/pdf.js,mozilla/pdf.js,nawawi/pdf.js,nawawi/pdf.js,macroplant/pdf.js,Shoobx/pdf.js,macroplant/pdf.js,timvandermeij/pdf.js,xavier114fch/pdf.js,mozilla/pdf.js,Snuffleupagus/pdf.js,timvandermeij/pdf.js,showpad/mozilla-pdf.js,mozilla/pdf.js,macroplant/pdf.js,nawawi/pdf.js,timvandermeij/pdf.js,Shoobx/pdf.js,showpad/mozilla-pdf.js,Snuffleupagus/pdf.js,Snuffleupagus/pdf.js