test: fix npm install test failing in some cases (#569)
test: fix npm install test failing in some cases (#569)

If you copy only part of node_modules, `npm install` may behave the same as `npm ci`.
This sometimes causes tests that check for identical timestamps to fail.

```js
assert.equal(beforeAwsSdkStat.ctimeMs, afterAwsSdkStat.ctimeMs)
```
motdotla/node-lambda,motdotla/node-lambda