[cfe] No error when an extension type implements two interfaces with different type parameters

[sgrekhov]

The following tests fail on CFE (works in analyzer):
https://github.com/dart-lang/co19/blob/master/LanguageFeatures/Extension-types/superinterfaces_of_extension_type_A03_t03.dart
https://github.com/dart-lang/co19/blob/master/LanguageFeatures/Extension-types/superinterfaces_of_extension_type_A03_t05.dart
They looks like

// SharedOptions=--enable-experiment=inline-class

class A<T> {}

extension type A_ET1<T>(A<T> _) implements A<T> {}

extension type A_ET2<T>(A<T> _) implements A<T> {}

// Analyzer:  The extension type 'ET' can't implement both 'A<int>' and 'A<num>' because the type
//          arguments are different. • conflicting_generic_interfaces
// CFE: no expected error
extension type ET(A<int> _) implements A_ET1<int>, A_ET2<num> {}
//             ^^
// [analyzer] unspecified
// [cfe] unspecified
main() {
  print(ET);
}

Tested on Dart SDK version: 3.3.0-edge.e285a5724831d547f03d34764c0c08de998548db (be) (Thu Oct 19 03:46:18 2023 +0000) on "linux_x64"