Fix crash in node when mixing sync/async resolvers

[chrskrchr]

trafficstars

Fixes #3528

Ensures that if executeFields encounters a mix of promises and thrown errors, the promises will be awaited before throwing the error.

[netlify[bot]]

✅ Deploy Preview for compassionate-pike-271cb3 ready!

Name	Link
🔨 Latest commit	880d3bd176d25d11e30ded6f3b8f2cecabbace5a
🔍 Latest deploy log	https://app.netlify.com/sites/compassionate-pike-271cb3/deploys/6348048c556859000a25e5f1
😎 Deploy Preview	https://deploy-preview-3706--compassionate-pike-271cb3.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site settings.

[chrskrchr]

@saihaj - could you take a look at this PR when you have a moment? A similar had been submitted and approved previously (so it might look familiar), but I don't want to mention that PR here for risk of tainting it with CLA issues like the last PR. 😬