Bitwuzla: Optimize memory usage

[daniel-raffler]

Hello,

this PR adds two optimizations for Bitwuzla to bring down memory usage:

• it adds an Evaluator to skip model generation in allSat
• it further optimizes extractVariablesAndUFs to avoid creating unnecessary Java proxies in the visitor

Here are some results from SVCOMP with a 60s time limit: SV-COMP26_no-overflow

The left column is before this PR, the middle is with the new Evaluator, and the right is with the extractVaraiblesAndUFs optimization (and the Evaluator)

And here's the scatter plot for a before-after comparison:

[baierd]

LGTM! Nice work!

I'll start a 900s run in CPAchecker that fits the initial problem that uncovered the problem. That way we can compare it properly (i already have results for current JavaSMT master).

[kfriedberger]

lgtm.

[baierd]

Results (w comparison to before) for the overflow category:
bitwuzla.overflow.cmp.results.2026-04-13_00-23-37.table.html

No regressions and only 123 out-of-memories now (546 before).
We can still try to find out whether we can do something for the other tasks, but this PR can definitely be merged!
Good job!