Flutter would like to have a way to test that all members which are accessed by name from native side are correctly annotated with @pragma('vm:entry-point') annotation.

Currently we print an error to the console, but this is not discoverable and can't be used for testing.

We should introduce a VM flag --verify-entry-points which turns on strict checking of @pragma('vm:entry-point') annotations. When this flag is turned on any attempt to access a member by name via C API should result in an error.

Then we should turn on this flag for Flutter so that we catch any issues with missing annotations as early as possible.

/cc @goderbauer