Upgrade confuse() function in corelib tests

tests/corelib/apply_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import "package:expect/expect.dart";
 import "symbol_map_helper.dart";
 
 // Testing Function.apply calls correctly.
 // This test is not testing error handling, only that correct parameters
 // cause a correct call.
 
 int test0() => 42;
 int test0a({int a}) => 37 + a;
 int test1(int i) => i + 1;
 int test1a(int i, {int a}) => i + a;
 int test2(int i, int j) => i + j;
 int test2a(int i, int j, {int a}) => i + j + a;
 
 class C {
   int x = 10;
   int foo(y) => this.x + y;
 }
 
 class Callable {
   int call(int x, int y) => x + y;
 }
 
-confuse() {
-  try {
-    throw [Function.apply];
-  } catch (e) {
-    return e[0];
-  }
-  return null;
-}
+@NoInline()
+@AssumeDynamic()
+confuse(x) => x;
 
 main() {
   testMap(res, func, map) {
     map = symbolMapToStringMap(map);
     Expect.equals(res, Function.apply(func, null, map));
     Expect.equals(res, Function.apply(func, [], map));
   }
   testList(res, func, list) {
     Expect.equals(res, Function.apply(func, list));
     Expect.equals(res, Function.apply(func, list, null));
     Expect.equals(res, Function.apply(func, list, new Map<Symbol, dynamic>()));
   }
   test(res, func, list, map) {
     map = symbolMapToStringMap(map);
     Expect.equals(res, Function.apply(func, list, map));
   }
   testList(42, test0, null);
   testList(42, test0, []);
   testMap(42, test0a, {"a": 5});
   testList(42, test1, [41]);
   test(42, test1a, [20], {"a": 22});
   testList(42, test2, [20, 22]);
   test(42, test2a, [10, 15], {"a" : 17});
 
   // Test that "this" is correct when calling closurized functions.
   var cfoo = new C().foo;
   testList(42, cfoo, [32]);
 
   // Test that apply works even with a different name.
-  var app = confuse();
+  var app = confuse(Function.apply);
   Expect.equals(42, app(test2, [22, 20]));
 
   // Test that apply can itself be applied.
   Expect.equals(42, Function.apply(Function.apply, [test2, [17, 25]]));
 
   // Test that apply works on callable objects.
   testList(42, new Callable(), [13, 29]);
 }