Changed size.json portion of javascript.js

The size.json portion of javascript.js didn't match the actual languages/javascript/size.json file; I believe this part of the reason why issue #659 kept occurring for me. When there were json errors in my example code, the script area would have references to a dated, no-longer-existent "convertSideLengthUnits" function, and I just noticed this function still resided in dist/javascript.js (until now).