MDD optimizations

[mondokm]

• Implement hashCode and equals methods in IdentityNextStateDescriptor,
• Use caching for sat check of a node
• Do not check satisfiability when checking models
• Fix Stmt flattener for IfElse

[sonarqubecloud]

Quality Gate passed

Issues
7 New issues
0 Accepted issues

Measures
0 Security Hotspots
70.8% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Benchexec test report for a selection of SV-Benchmarks (correct / incorrect / all):

Rundefinition	COMPLEX	EMERGENT	HORN
SV-COMP25_no-data-race	✅ (59 / 0 / 89) HTML/CSV	✅ (35 / 0 / 71) HTML/CSV	✅ (20 / 0 / 83) HTML/CSV
SV-COMP25_no-overflow	✅ (16 / 0 / 48) HTML/CSV	❓ (0 / 0 / 38) HTML/CSV	❓ (0 / 0 / 90) HTML/CSV
SV-COMP25_termination	✅ (1 / 0 / 205) HTML/CSV	✅ (1 / 0 / 204) HTML/CSV	✅ (14 / 0 / 306) HTML/CSV
SV-COMP25_unreach-call	✅ (18 / 0 / 96) HTML/CSV	✅ (16 / 0 / 95) HTML/CSV	✅ (10 / 0 / 193) HTML/CSV
SV-COMP25_valid-memcleanup	❓ (0 / 0 / 66) HTML/CSV	❓ (0 / 0 / 66) HTML/CSV	❓ (0 / 0 / 66) HTML/CSV
SV-COMP25_valid-memsafety	✅ (34 / 0 / 314) HTML/CSV	✅ (2 / 0 / 268) HTML/CSV	❓ (0 / 0 / 403) HTML/CSV