quickjs-wasi's JSException constructor runs `delete this.stack` so V8's
own stack property stops shadowing the class's stack accessor; scriptc
fenced the delete, so every guest exception reaching the host threw the
fence error. Compiled errors keep the trace internally and class dispatch
already reads the accessor, so the delete now evaluates its receiver and
nothing else, for Error subclasses whose chain declares a stack getter.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
