Incremental Statix

[AZWN]

This PR enables using Statix with different solver modes. The changes are as follows:

• A statix-solver-mode = traditional | concurrent | incremental option is added to the constraint-analyzer section of the CFG language.
• When compiling a language, its AnalyzeMulti task will have the solver mode integrated in its StatixProjectConfig context object.
• The replicated primitives StatixSolverModePrimitive and StatixConcurrentEnabledPrimitive read this solver mode. They receive the language identifier by calling the language_components stratego primitive (implemented by spoofax2.common).

As the ConstraintAnalyzerContext already manages the state, and provides the previous result to the constraint analyzer, no additional effort needs to be undertaken to manage (serialize) previous solver states.

Items still to do:

• Fix PR comments from Gabriel
• Test, profile and enable concurrent solver for Dynamix (see Base implementation of Dynamix, Tim #111)

[AZWN]

It is worth mentioning that there will be an innocent stacktrace in the console when there is no lib/stxlibs file. It is completely safe that these files do not exist, the (warning-level) logging is just a bit aggressive. I'd be happy to take any suggestions to solve this, but I'd rather not touch the statix runtime itself for this too much.

[MeAmAnUsername]

Does this mean that the Statix solver can be either concurrent or incremental but not both? Ideally it would be both at the simultaneously, or choose one or the other depending on which of the two is expected to be the fastest.

[AZWN]

That is not in particular a concern of this PR, but the incremental solver is always concurrent at the same time.

[Gohla]

For some reason I never got a notification about this. I will review and merge this next week.

[Gohla]

Looks good apart from a couple of small changes!