CFlite doesn't seem to show backtraces by default when bugs aren't reproducible

https://github.com/evverx/elfutils/runs/4541456435?check_suite_focus=true
```
2021-12-16T00:15:02.4107312Z INFO: Seed: 1337
2021-12-16T00:15:02.4497204Z INFO: Loaded 1 modules (15250 inline 8-bit counters): 15250 [0x7dee1b, 0x7e29ad),
2021-12-16T00:15:02.4502091Z INFO: Loaded 1 PC tables (15250 PCs): 15250 [0x747a30,0x783350),
2021-12-16T00:15:02.4510120Z INFO: 7 files found in /github/workspace/cifuzz-corpus/fuzz-dwfl-core
2021-12-16T00:15:02.4511154Z INFO: -max_len is not provided; libFuzzer will not generate inputs larger than 249851 bytes
2021-12-16T00:15:02.4516748Z INFO: seed corpus: files: 7 min: 568b max: 249851b total: 279535b rss: 70Mb
2021-12-16T00:15:28.6084552Z 2021-12-16 00:15:28,513 - root - INFO - Fuzzer: fuzz-dwfl-core. Detected bug.
2021-12-16T00:15:28.6095082Z 2021-12-16 00:15:28,573 - root - INFO - Trying to reproduce crash using: /tmp/tmp1zc5yps3/tmp83o6vkm6.
2021-12-16T00:15:29.3282172Z 2021-12-16 00:15:29,325 - root - INFO - Reproduce command returned: 0. Not reproducible on /github/workspace/build-out/fuzz-dwfl-core.
2021-12-16T00:15:29.3303060Z 2021-12-16 00:15:29,326 - root - INFO - Crash is not reproducible.
2021-12-16T00:15:29.3436231Z 2021-12-16 00:15:29,341 - root - INFO - Deleting corpus and seed corpus of fuzz-dwfl-core to save disk.
2021-12-16T00:15:29.3456056Z 2021-12-16 00:15:29,344 - root - INFO - Deleting fuzz target: fuzz-dwfl-core.
2021-12-16T00:15:29.3475358Z 2021-12-16 00:15:29,345 - root - INFO - Done deleting.
2021-12-16T00:15:29.3488252Z 2021-12-16 00:15:29,347 - root - INFO - Fuzzer fuzz-dwfl-core finished running without reportable crashes.
2021-12-16T00:15:29.3543613Z 2021-12-16 00:15:29,353 - root - INFO - No crashes in /github/workspace/out/artifacts. Not uploading.
```
Looking at "report-unreproducible-crashes: false" it seems I can flip that flag to make it "reportable" but I think it would be great if backtraces were shown by default even when bugs aren't reproducible.