fix: remove old/duplicate Haskell runtime initialization code

[zshipko]

No description provided.

[nilslice]

@bhelx wasnt there some mono / c# runtime code that needs to be started upon plugin initialization? wondering if this is applicable there.

[zshipko]

We should use the new Runtime enum for that. This is code that was supposed to be removed after adding the nicer runtime initialization interface.

[nilslice]

Definitely agree - mostly leaving this as a note to connect some dots between here and convos on Discord.

But I also didn't realize this code was so specific to Haskell on first glance 😆

[bhelx]

Yeah, the Csharp PDK will be based on mono. It needs _start to be called to initialize everything or else it crashes. I'm a bit confused why the runtime doesn't do it when you enable wasi. Will follow back up when we get further along with development. It could be a quirk with that one PDK.

[zshipko]

I don't think WASI will really initialize language specific runtimes - to initialize Haskell hs_init is called in _start before the user-defined main function is executed. I was able to re-export that function by passing --export=hs_init to wasm-ld during compilation. Then calling hs_init lets us call other functions without going through _start - maybe there is something similar for mono?