test: surface compute sanitizer logs

[WilliamK112]

Summary

• print fresh Compute Sanitizer log contents to stderr when the sanitizer wrapper exits nonzero
• preserve the original sanitizer exit status and existing sanitizer_for_pid_*.log files
• keep success-path output quiet

Closes #1337.

Validation

• git diff --check
• bash -n build/sanitizer-java/bin/java
• ran the wrapper with a fake failing compute-sanitizer; verified stderr includes the simulated sanitizer report and the wrapper exits with the sanitizer status
• ran the wrapper with a fake successful compute-sanitizer; verified stderr remains empty and the wrapper exits 0