Replace XMLHttpRequest usage with the Fetch API in `inlineImages` (in `test/driver.js`)
Replace XMLHttpRequest usage with the Fetch API in `inlineImages` (in `test/driver.js`)

This is the final part in a series of patches that try to re-implement PR 14287 in smaller steps.

Besides converting `inlineImages` to use the Fetch API, this patch also combines the `inlineImages` and `resolveImages` functions since they are always used together.

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