Prevent unhandled promise rejections from terminating the DA
Prevent unhandled promise rejections from terminating the DA

Fixes #3916 by restoring the previous behaviour on older Node versions.

Opened #3918 for a proper fix to any places that are allowing promises to go unhandled.

Dart-Code/Dart-Code,Dart-Code/Dart-Code,Dart-Code/Dart-Code,Dart-Code/Dart-Code,Dart-Code/Dart-Code