tests: enhance TAP error reporting with more diagnostic information

tests: enhance TAP error reporting with more diagnostic information

Add enhanced diagnostic output for test failures including:
- Exception type and detailed messages
- Process return codes and failed commands
- Process output and stderr
- Working directory and test environment info

This improves debugging of test failures by providing more context
about what went wrong during test execution.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>