Optimize `convertOpList` in `svg.js` by computing the operator ID mapping only once
Optimize `convertOpList` in `svg.js` by computing the operator ID mapping only once

There is no need to recompute this for every operator list we encounter.

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