Fix error handling in test_harness.py
If this was run under python3 and a compilation error occurred,
it would throw another exception while trying to report the error.
[ci skip]
@@ -116,7 +116,7 @@ def build_program(source_files, image_type='bare-metal', opt_level='-O3', cflags
else:
return ELF_FILE
except subprocess.CalledProcessError as exc:
- raise TestException('Compilation failed:\n' + exc.output)
+ raise TestException('Compilation failed:\n' + exc.output.decode())
class TimedProcessRunner(threading.Thread):
