Fix different priority of getter if by name or property on different namespaces

[wsxarcher]

When a subclass declares a field with the same local name as a private (or internal) field in a superclass, AVM2 property lookups via bracket access (this["field"]) were resolving to the wrong slot.

The priority is reversed from where they are present in the set with priority to publics.

Traced with Flashplayer 32

[Lord-McSweeney]

Unfortunately I think the proper solution to this is a little more complicated. We need to change our vtable implementation so that each vtable first attempts to lookup a property on only its own map, then falls back to its parent vtable. See this SWF: chainedvt.swf.zip

It outputs

subclass-field1
subclass-field1
superclass-field2
superclass-field2

with this PR, but

subclass-field1
subclass-field1
subclass-field2
subclass-field2

with FP.

Since Subclass's vtable is the top-most, in FP the property lookups all find properties on it, which means none of the property lookups get a chance to look at Superclass's vtable.

[wsxarcher]

Fixing the insertion order rather than the lookup seems to fix also your case without touching the vtable, I added your test.