Migrate test block 30 + corelib portion of block 31 to Dart 2.0.

tests/corelib_strong/uri_scheme_test.dart

-// Copyright (c) 2013, 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";
-
-void testInvalidArguments() {
-  Expect.throws(() => new Uri(scheme: "_"), (e) => e is FormatException);
-  Expect.throws(() => new Uri(scheme: "http_s"), (e) => e is FormatException);
-  Expect.throws(
-      () => new Uri(scheme: "127.0.0.1:80"), (e) => e is FormatException);
-}
-
-void testScheme() {
-  test(String expectedScheme, String expectedUri, String scheme) {
-    var uri = new Uri(scheme: scheme);
-    Expect.equals(expectedScheme, uri.scheme);
-    Expect.equals(expectedUri, uri.toString());
-    uri = Uri.parse("$scheme:");
-    Expect.equals(expectedScheme, uri.scheme);
-    Expect.equals(expectedUri, uri.toString());
-  }
-
-  test("http", "http:", "http");
-  test("http", "http:", "HTTP");
-  test("http", "http:", "hTTP");
-  test("http", "http:", "Http");
-  test("http+ssl", "http+ssl:", "HTTP+ssl");
-  test("urn", "urn:", "urn");
-  test("urn", "urn:", "UrN");
-  test("a123.432", "a123.432:", "a123.432");
-}
-
-main() {
-  testInvalidArguments();
-  testScheme();
-}