LDrawLoader: Start removing stored derivative data during initial parse (#23139)
LDrawLoader: Start removing stored derivative data during initial parse (#23139)

* generate face normals only as needed

* Remove unused variable

* comment update
makc/three.js.fork,greggman/three.js,gero3/three.js,06wj/three.js,fyoudine/three.js,greggman/three.js,fyoudine/three.js,looeee/three.js,mrdoob/three.js,Liuer/three.js,donmccurdy/three.js,mrdoob/three.js,aardgoose/three.js,donmccurdy/three.js,Liuer/three.js,06wj/three.js,WestLangley/three.js,gero3/three.js,makc/three.js.fork,jpweeks/three.js,jpweeks/three.js,WestLangley/three.js,looeee/three.js,aardgoose/three.js