nit: now that `finalizeInGC()` calls `cleanMustHandleValuesIfNecessary()` itself, this call has no reader — the `appendUnbarriered` loop it used to serve is gone, and both remaining consumers (`finalizeInGC`, `compileInThreadImpl`) clean for themselves. It's harmless (idempotent, early-returns on the flag), but keeping a call that mutates `m_mustHandleValues` state directly under a comment saying "m_mustHandleValues is not visited here" reads confusingly; consider dropping it.