The 'heapStats({dump: "blocks"})' test accesses `main.blocks` without first asserting `main` is defined, unlike the parallel 'dump: true' test which correctly guards with `expect(main).toBeDefined()`. If `heaps.find(h => h.seq === 0)` returns `undefined` for any reason, the test will throw a `TypeError: Cannot read properties of undefined (reading 'blocks')` instead of a descriptive assertion failure.

The new heapStats dump section in `functionMemoryUsageStatistics` has two issues: (1) `mi_stats_get_json` returning null silently omits the `mimalloc` property entirely, breaking the stable shape callers expect — it should always emit `jsNull()` as a fallback; (2) the dump section calls `arg0.getObject()->get()` and `dump.toBoolean()` — both can throw via Proxy traps or `Symbol.toPrimitive` — but the function has no `DECLARE_THROW_SCOPE` and no `RETURN_IF_EXCEPTION` guards, so a pending JS excep