Use thisProcess instead of Processor activeProcess

[jordanmontt]

thisProcess has a special bytecode so it does not produce a message send

[jordanmontt]

I tried to replace the process := Process activeProcess with thisProcess and it breaks several tests. I need to investigate further

[guillep]

This will also degrade performance unless we add JIT compiler support for it.

[jordanmontt]

This will also degrade performance

Using process := Process activeProcess will degrade performance?

[guillep]

no, doing process := thisProcess will degrade performance if not JIT compiled.
And afterwards, it should slightly improve performance too (and remove message sends that could be meta-unsafe).

[guillep]

pharo-project/pharo-vm#1037