Organise members of SymbolHelpers.
Use name-based pattern matching in backend
Make sure genIcode and genASM compile.

They are using primitives and opcodes that were extracted to objects.
Use name-based pattern matching for deconstructors, using same instances.

Saves allocations but breaks thread-safety of  BackendInterface.
Implement BackendInterface for scalac
Start using ScalacBackendInterface.
Fix initialization order problem.