Another Different Struct for IR

[Lol3rrr]

Problem

Currently the IR can not really be cloned/copied in the Sense that you get independant Versions of it. This is very Problematic because it hinders the Options for Scaling the Optimizer as it cant run in in parallel if it needs access to information about other Functions, like for inlining.

Old-Design

The Old Design relies on Arc and WeakPointer to represent the IRs Controlflow, which works fine as it was intended, however as already noted above, this does not really allow for proper cloning/copying to create independant Objects that can be used concurrently.

New-Design

Add a new Representation where each Function contains a List of Blocks and then each Block is identified by its index in that List. All references to other Blocks are then replaced with their Index. This makes the entire Data Structure easily clonable and also makes it easier to keep track of everything.
There should also be a way to easily convert between these Formats as most of the Compiler will probably continue to use the Old-Design and just adopt the New-Design where needed, like in the Optimizer.