Remove Expect from core library.

tests/language/named_parameters2_test.dart

Index: tests/language/named_parameters2_test.dart
diff --git a/tests/language/named_parameters2_test.dart b/tests/language/named_parameters2_test.dart
index e6c037dca518c40779acf13f049fdeb97e0a8f2a..22ae60350ffab95e91a808fdcdc910c147a9fd0c 100644
--- a/tests/language/named_parameters2_test.dart
+++ b/tests/language/named_parameters2_test.dart
@@ -4,6 +4,8 @@
 // Dart test program for testing named parameters.
 // You may not provide the same parameter as both a positional and a named argument.
 
+import "package:expect/expect.dart";
+
 int test(int a, [int b]) {
   return a;
 }