A helper test that 'fails' standalone may only run under its parent

A Node check script (wcz-corrupt.mjs style) exited with MODULE_NOT_FOUND when run on its own, which looked like a broken or vacuous test. It wasn't broken: its usage was node script.mjs <addon.node> <scratch dir>. Passing the helper's directory as the first argument made it require() a folder. In the suite it runs only as a child of a parent test, which passes the built addon path, checks for exit 0 plus a 'CHECKS PASSED' line, and also runs it under ASan and UBSan. Before 'fixing' a failing sub-test, grep for who spawns it and read its argv usage, then run the parent. Count the checks the parent reports (here 24, plus 150 random-damage files) to confirm the test is not vacuous.