Remove Expect from core library.

tests/language/generic_inheritance_test.dart

Index: tests/language/generic_inheritance_test.dart
diff --git a/tests/language/generic_inheritance_test.dart b/tests/language/generic_inheritance_test.dart
index 487c9ca8802d3b4b12f295d601e88a2e7fcd8d14..fec8adb6343264dcf6c7713734e530e1cb8edd7b 100644
--- a/tests/language/generic_inheritance_test.dart
+++ b/tests/language/generic_inheritance_test.dart
@@ -5,6 +5,8 @@
 // Test verifying that the type argument vector of subclasses are properly
 // initialized by the class finalizer.
 
+import "package:expect/expect.dart";
+
 class A<T> { A(); }
 class B extends A<Object> { B(); }
 class C extends B { C(); }