Autotuner only enables relational analysis for at most 2 globals

[sim642]

While checking https://github.com/goblint/analyzer/pull/1821#issuecomment-3342492386, I found out the following surprising thing: the autotuner only enables relational analysis for at most 2 globals: https://github.com/goblint/analyzer/blob/529013137ad4de9d020b47dcfc7a553d1e677766/src/autoTune.ml#L435-L447

We should really look into this because we could be shooting ourselves in the foot with such a low limit. SV-COMP benchmarks often use global variables for no good reason (over locals) because code quality doesn't matter. This also makes relational Mutex-Meet mostly useless.