Fixed incorrect default trace-dir path

[arminzavada]

The previous inputOptions.model.parent returns null if the model is directly in the working directory. Instead, the parentFile should be used, as that will respect relative paths as well.

[github-actions]

❗ Please modify build.gradle.kts to contain a later version than 6.27.5. Current version is 6.27.5.

[github-actions]

❗ Please run ./gradlew spotlessApply on your branch to fix formatting.

[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 / 88) HTML/CSV	✅ (31 / 0 / 67) HTML/CSV	✅ (20 / 0 / 83) HTML/CSV
SV-COMP25_no-overflow	✅ (17 / 0 / 49) HTML/CSV	❓ (0 / 0 / 37) HTML/CSV	❓ (0 / 0 / 87) HTML/CSV
SV-COMP25_termination	✅ (1 / 0 / 205) HTML/CSV	✅ (1 / 0 / 13) HTML/CSV	✅ (14 / 0 / 306) HTML/CSV
SV-COMP25_unreach-call	✅ (18 / 0 / 96) HTML/CSV	✅ (16 / 0 / 93) HTML/CSV	✅ (10 / 0 / 190) 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 / 317) HTML/CSV	✅ (3 / 0 / 283) HTML/CSV	❓ (0 / 0 / 271) HTML/CSV