Migrate block 37, language/arithmetic2 ... /async_await_syntax_test.

tests/language/assertion_initializer_const_function_test.dart

-// Copyright (c) 2017, 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.
-// VMOptions=--assert_initializer
-//
-// Dart test program testing assert statements.
-
-import "package:expect/expect.dart";
-
-class C {
-  static bool staticTrue() => true;
-  final int x;
-  const C(this.x);
-  // The expression *is* compile-time constant, but not a bool value.
-  // Static warning, runtime always fails assertion.
-  const C.bc01(this.x, y)
-      : assert(staticTrue)  //# 01: static type warning
-      ;
-}
-
-main() {
-  bool checkedMode = false;
-  assert(checkedMode = true);
-  if (checkedMode) {                                              //# 01: continued
-    Expect.throws(() => new C.bc01(1, 2), (e) => e is TypeError); //# 01: continued
-  } else {                                                        //# 01: continued
-    Expect.equals(1, new C.bc01(1, 2).x);
-  }                                                               //# 01: continued
-}