[CFE] Definitions from main library are not visible in augmentation library

[sgrekhov]

According to the Augmentation libraries spec

Declarations in any augmentation or the main library are visible to all of the others, including private ones.

But definitions from the main library are not visible in augmentation lib in CFE

// main_lib.dart
// SharedOptions=--enable-experiment=macros

import augment 'augh_lib.dart';

class C1 {
  String get y => "y";
}

// augh_lib.dart
// SharedOptions=--enable-experiment=macros

library augment 'main_lib.dart';

main() {
  print(C1); // Analyzer: Ok. CFE: Error: Undefined name 'C1'.
}

Tested on Dart SDK version: 3.4.0-194.0.dev (dev) (Sat Mar 2 00:04:28 2024 -0800) on "windows_x64"