Add used classes to class table at snapshot time not during GC
Add used classes to class table at snapshot time not during GC

Speed-Pad/online,the-impossible-quiz-revisited/the-impossible-quiz-revisited.github.io,Speed-Pad/online,the-impossible-quiz-revisited/the-impossible-quiz-revisited.github.io,sebastianconcept/SqueakJS,the-impossible-quiz-revisited/the-impossible-quiz-revisited.github.io,bertfreudenberg/SqueakJS,bertfreudenberg/SqueakJS,sebastianconcept/SqueakJS,bertfreudenberg/SqueakJS,Speed-Pad/online,the-impossible-quiz-revisited/the-impossible-quiz-revisited.github.io,sebastianconcept/SqueakJS,bertfreudenberg/SqueakJS