Remove dead code in Debugging-Core

[jecisc]

Debugging-Core is a mess. It has dead code. It has a lot of code that is only used in one other specific package in pharo (so the code could move there). It has code used in the Kernel but not present in the kernel.

Here is a first iteration to clean this package by removing most of the dead code and cleaning a few dependencies problems.

• Remove BlockLocalTempCounter that was only used in the squeak decompiler
• Remove InstVarRefLocator that is references only by methods with no sender (this one should be a flag in the header because otherwise this is too slow Marcus told me)
• Remove the whole concept of longPrintString from object that is used only on IR and compilled methods and fix problems that CompiledCode was implementing methods only working on CompiledMethod
• Remove lot of extensions with no sender

Next step is to move lot of the remaining classes in OpalCompiler-Tests because they are used only in those tests and flashback tests