Idea: Improvement for intermediate language

[peq]

This is just an idea to restructure the internal Wurst code, nothing about Wurst language features.

Restructure intermediate language to allow for unstructured control flow (goto) and remove ifs/loops.

Then use something like people do for web assembly (relooper etc. to go back to Jass / structured control flow):

https://medium.com/leaningtech/solving-the-structured-control-flow-problem-once-and-for-all-5123117b1ee2

This has a few advantages:

• Would make it easy to generate code for constructs like `continue (#634)
• Would make it easier to extend the function inliner to functions with multiple return statements.
• Might simplify some optimizations
• In the future, it might make other features easier to implement (delimited continuations or async/await)
• It's required if we want to use LLVM as an optimizer step.
• It's cool to implement this M;D

Challenges:

• Original algorithm assumes continue and break statements with labels. Probably have to use variables to handle this.