* avm2: Use RawTable to implement 'public index' iteration
This makes our implementation more closely aligned with avmplus.
In particular, it's now possible to delete keys from an object
while iterating without disturbing the iteration order (as long
as those keys were already produced by the iterator).
This is based on @Bale001's work on RawTable-based iteration
A few tests had their output changed (they depend on the exact
object iteration order, and don't neccessarily match Flash Player
exactly).
* Use Cell to store index fields
* Remove outdated comment
* core: add temporary, ruffle-internal copy of `gc-arena` crate
This will allow bumping the upstream `gc-arena` version while
reexporting our own version of the old `GcCell` API, so that
Ruffle's code can be gradually migrated.
Once the migration is done, this crate should be removed.
* core: bump `gc-arena` to kyren/gc-arena#56
Add back the removed `GcCell` to our internal facade crate
* core: bump `gc-arena` to current master
This bump renames `Gc::allocate` to `Gc::new`
* core: rename `GcCell::allocate` to `GcCell::new`, to match `Gc`
* core: bump gc-arena to (slighly after) v0.3.1
Add typedefs for old `*Context` names in the gc-arena facade crate
* core: replace uses of `CollectionContext<'_>` by `&Collection`
* core: Add `gc()` convenience method for `*Context` and `Activation` types
This allows shortening most instances of `[activation.]context.gc_context`
to `activation.gc()` or `context.gc()` (but not all instances, because of
borrowck) Note that this doesn't actually do these shortenings to avoid
major code churn.
TÖRÖK Attila