Allow Z3 mappings to create contexts without models

[filipeom]

During symbolic executions, contexts without models are slightly faster than when this option is enabled. Models are only used for test-suite generation at the end of the analysis, accounting for only a fraction of the executed queries.

[zapashcanon]

IIRC @chambart tried this and it was not making it any faster

[filipeom]

I tested it as well, and it doesn't appear to have any impact. However, Z3 consistently generates models, whether you set the 'model' option to 'true' or 'false,' so I may be overlooking something

[zapashcanon]

Yes, or Z3 may be completely ignoring this option

[filipeom]

It could be, I'll take a look into it 😄