avm1: Migrate flash.geom.Point from Rust to ActionScript

[relrelb]

Description

Make use of the playerglobal infrastructure introduced in #23730 to implement flash.geom.Point using pure ActionScript.

Testing

Existing tests now match closer Flash's behavior, and Gnash's Point-v8 test now passes cleanly.

Checklist

• I, a human, have self-reviewed this PR and fully understand the changes within.
• I have made or updated tests where possible.
• All of my commits are properly scoped, compile successfully, and pass all tests.
• This PR does not make sense to split up into smaller PRs.
• An LLM was involved in the authoring of this code.

[moulins]

As discussed on Discord, I'm not entirely convinced by the decoupling of case sensitivity and SWF version; I think it should split it in a separate PR so we can determine if it's the correct approach separately.
To keep Point (mostly) working, you could instead use [6, 8] instead of [6, 7] for the SWF versions in Avm1::run_stack_frame_for_globals (EDIT: and move the flash version-gating at the end of globals.as).

[kjarosh]

The AS code and tests LGTM, thank you! I haven't looked at the swf version stuff yet. It also looks like we could rearrange commits and squash some of them, the history is quite complicated.

[relrelb]

The AS code and tests LGTM, thank you! I haven't looked at the swf version stuff yet. It also looks like we could rearrange commits and squash some of them, the history is quite complicated.

Done. WDYT?

[kjarosh]

Thank you! Looks great!