Keep a compact enum-index-to-entry-index vector beside the hash-sorted
entry storage. This preserves the sorted lookup layout while letting
insertion-order enumeration walk the visible descriptor prefix directly.
Replace the lazy per-shape OrderedHashMap cache for non-dictionary
shapes with a GC-allocated descriptor array. Store descriptors in hash
order for lookup while keeping an enum index so callers can still walk
properties in insertion order.
Keep dictionary shapes on the mutable OrderedHashMap path, and migrate
callers that enumerated Shape::property_table() to the new insertion
order iterator. Cap descriptor arrays to their compact u16 index range
and keep larger dictionary shapes on the mutable table path across
prototype transitions and prototype clones.
Add coverage for setting the prototype of a dictionary object with more
than 65536 named properties.
