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 df08036e381936a2cfa3d61bb505db96fe3ae474..0581a9cc8b8d68f4bbdc0a29598a6d90004916fb 100644
--- a/runtime/vm/dart_api_impl_test.cc
+++ b/runtime/vm/dart_api_impl_test.cc
@@ -6448,6 +6448,11 @@ 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"
@@ -6586,6 +6591,11 @@ 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"