Remove Expect from core library.

runtime/vm/dart_api_impl_test.cc

Index: runtime/vm/dart_api_impl_test.cc
diff --git a/runtime/vm/dart_api_impl_test.cc b/runtime/vm/dart_api_impl_test.cc
index 61c4dbc70dc97307aec92312e9614aee1505273b..f00f6cd39522a2110d6a9812e227ae1e945da8d6 100644
--- a/runtime/vm/dart_api_impl_test.cc
+++ b/runtime/vm/dart_api_impl_test.cc
@@ -6648,6 +6648,11 @@ TEST_CASE(NativeFunctionClosure) {
       "  int bar43(int i, int j, int k) {\n"
       "    var func = foo4; return func(i, j, k); }\n"
       "}\n"
+      "class Expect {\n"
+      "  static void equals(x, y) {\n"
+      "    if (x != y) throw new Error('not equal');\n"
+      "  }\n"
+      "}\n"
       "int testMain() {\n"
       "  Test obj = new Test();\n"
       "  Expect.equals(1, obj.foo1());\n"
@@ -6786,6 +6791,11 @@ TEST_CASE(NativeStaticFunctionClosure) {
       "  int bar43(int i, int j, int k) {\n"
       "    var func = foo4; return func(i, j, k); }\n"
       "}\n"
+      "class Expect {\n"
+      "  static void equals(x, y) {\n"
+      "    if (x != y) throw new Error('not equal');\n"
+      "  }\n"
+      "}\n"
       "int testMain() {\n"
       "  Test obj = new Test();\n"
       "  Expect.equals(0, Test.foo1());\n"