drizzle-mysql-smoke: fixture throws 'Cannot assign to read only property uniqueName' where node does not

[proggeramlug]

First tier=full run in weeks (31935729773). MySQL service healthy, build and compile clean; the compiled drizzle fixture exits 1 at runtime:

TypeError: Cannot assign to read only property 'uniqueName' of object '#<Object>'

A readonly/frozen-property write that node accepts (sloppy-ish assignment path in drizzle-orm) throws in Perry-compiled code. Related in flavor to the test_gap_prop_plan_cache_invalidation triage (#8198's fragment: js_throw_type_error_immutable_write has no receiver awareness), but this one is a semantic difference, not just message text: node does not throw here.

Tracker refs: #488/#489 (drizzle+MySQL compile-as-package).