Add expected CFE errors on concrete 'index' members (#1330)

diff --git a/LanguageFeatures/Enhanced-Enum/implementing_enum_A01_t01.dart b/LanguageFeatures/Enhanced-Enum/implementing_enum_A01_t01.dart
index e5749f0..9eaa542 100644
--- a/LanguageFeatures/Enhanced-Enum/implementing_enum_A01_t01.dart
+++ b/LanguageFeatures/Enhanced-Enum/implementing_enum_A01_t01.dart
@@ -27,6 +27,8 @@
 // [analyzer] unspecified
 // [cfe] unspecified
   int get index => 42;
+//        ^^^^^
+// [cfe] unspecified
 }
 
 main() {
diff --git a/LanguageFeatures/Enhanced-Enum/implementing_enum_A01_t04.dart b/LanguageFeatures/Enhanced-Enum/implementing_enum_A01_t04.dart
index 8f83cdc..d8ba025 100644
--- a/LanguageFeatures/Enhanced-Enum/implementing_enum_A01_t04.dart
+++ b/LanguageFeatures/Enhanced-Enum/implementing_enum_A01_t04.dart
@@ -32,6 +32,8 @@
 // [analyzer] unspecified
 // [cfe] unspecified
   int get index => 42;
+//        ^^^^^
+// [cfe] unspecified
   int foo() => 42;
 }
 
@@ -40,6 +42,8 @@
 // [analyzer] unspecified
 // [cfe] unspecified
   int get index => 42;
+//        ^^^^^
+// [cfe] unspecified
   int foo() => 42;
 }
 
diff --git a/LanguageFeatures/Enhanced-Enum/implementing_enum_A01_t06.dart b/LanguageFeatures/Enhanced-Enum/implementing_enum_A01_t06.dart
index e422ffe..38ea693 100644
--- a/LanguageFeatures/Enhanced-Enum/implementing_enum_A01_t06.dart
+++ b/LanguageFeatures/Enhanced-Enum/implementing_enum_A01_t06.dart
@@ -33,6 +33,8 @@
 // [analyzer] unspecified
 // [cfe] unspecified
   int get index => 1;
+//        ^^^^^
+// [cfe] unspecified
 }
 
 class C2 implements M2 {
@@ -40,6 +42,8 @@
 // [analyzer] unspecified
 // [cfe] unspecified
   int get index => 2;
+//        ^^^^^
+// [cfe] unspecified
 }
 
 class C3 with M3 {
@@ -47,6 +51,8 @@
 // [analyzer] unspecified
 // [cfe] unspecified
   int get index => 3;
+//        ^^^^^
+// [cfe] unspecified
 }
 
 main() {