avm2: Fix a bunch of API mismatches (versions/base class/accessors)

[Dinnerbone]

It's not everything, we have some issues remaining, but it's a pretty good chunk

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Remaining issues if anyone else wants to tackle those:

String static has extra method "fromCharCode"

This is technically correct, the worst kind of correct. Flash doesn't define it on the class, somehow. I didn't care enough to figure out why.

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flash.accessibility.AccessibilityImplementation has extra method "get_selectionActiveIndex"
flash.accessibility.AccessibilityImplementation has extra method "get_selectionAnchorIndex"

Should be gated behind API 736 which ruffle doesn't support

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flash.display3D.Context3D variable "maxBackBufferWidth"'s access should be "readwrite", actually "readonly"
flash.display3D.Context3D variable "maxBackBufferHeight"'s access should be "readwrite", actually "readonly"

Didn't really feel like touching context3d stuff :D

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flash.events.GestureEvent has extra variable "controlKey"
 
flash.events.KeyboardEvent has extra variable "controlKey"
flash.events.KeyboardEvent has extra variable "commandKey"
 
flash.events.PressAndTapGestureEvent has extra variable "controlKey"
 
flash.events.TransformGestureEvent has extra variable "controlKey"

I couldn't find a consistent answer on what these should be gated behind, the docs and playerglobals seem inconsistent.

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flash.net.SharedObject variable "data"'s access should be "readonly", actually "readwrite"
flash.net.SharedObject has extra variable "_ruffleName" (uri "__ruffle__")

Looked too scary

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flash.net.URLLoader variable "bytesTotal"'s access should be "readwrite", actually "readonly"
flash.net.URLLoader variable "bytesLoaded"'s access should be "readwrite", actually "readonly"

Also scary

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flash.system.IME has extra variable "isSupported"

Docs were inconsistent with playerglobals