If Adobe was smart, they'd have started working on am asmjs (later WebAssembly) + webgl output for Flash a long time ago.
Alas they're not exactly forward-planning and let the platform die, and its tools fizzle. Today there's already better alternatives that do things more cleanly/natively (like Pixijs). If you use TypeScript with Pixijs, it's like having a much more advanced ActionScript, better development tools (your browser's devtools), and better performance. You lose a "stage" for free drawing, but that was more often than not a misused feature anyway (and one that has good alternatives in the DOM/JS world anyway).
And for a while they even had a C/C++ compiler for the Flash VM.
So if they really cared, it isn't something that should be too hard for them.
Failing that, it might be an interesting project for a compiler hacker without ideas.
In any case, I see it more like preserving many of the games written in Flash.
Someone is porting TypeScript to WASM, named AssemblyScript.
It won't surprise me to see a WebAssembly backend for Flash.