test: reap the timed-out test before its return code is used

Review catch. The TimeoutExpired handler called kill() and drained stdout
but never wait()ed, so fop.returncode stayed None -- and the shared exit
path below evaluates:

    rc += abs(int(fop.returncode))

which raises TypeError on None. The first timed-out test would therefore
abort the whole group as a Python exception instead of failing one test.

Latent until now: the timeout could never fire while the read loop blocked
in readline(), so this path was unreachable. Enabling the timeout in the
previous commit makes it reachable, so it has to be fixed in the same PR.

wait() after the drain yields -SIGKILL, so abs(int(...)) contributes 9 and
the timed-out test is correctly scored as failed. Verified directly:
returncode None before wait(), -9 after.

Also switches the drain's decode to errors='replace', matching the main
read loop -- a hung test is exactly the case likely to emit a truncated
multi-byte sequence, which would otherwise throw inside the handler.

Author: renecannao

test/scripts/bin/proxysql-tester.py

@@ -886,7 +886,15 @@ def disk_usage():
                     self.padmin_command(f"LOGENTRY '{TAP} test {fo_num+1}/{len(tap_tests)} \'{os.path.basename(fo_cmd)}\' timed out after {tap_timeout} seconds'")
                     # Drain any remaining output
                     for line in fop.stdout:
-                        log.debug(f"msg: {line.decode('utf-8').strip()}")
+                        log.debug(f"msg: {line.decode('utf-8', 'replace').strip()}")
+                    # Reap the child. kill() signals but does not wait, so
+                    # returncode stays None until we do -- and the shared exit
+                    # path below evaluates abs(int(fop.returncode)), which
+                    # raises TypeError on None. That path was unreachable while
+                    # the timeout could never fire; now that it can, a timed-out
+                    # test would abort the whole group instead of failing one
+                    # test. wait() yields -SIGKILL, so the test scores non-zero.
+                    fop.wait()
                 except Exception as e:
                     log.critical(f"TAP test {fo_num+1}/{len(tap_tests)} '{os.path.basename(fo_cmd)}' - test threw an exception !!!: {e}")
                     self.padmin_command(f"LOGENTRY '{TAP} test {fo_num+1}/{len(tap_tests)} \'{os.path.basename(fo_cmd)}\' - test threw an exception !!!'")