Remove use of deprecated test functions.

tests/html/dom_isolates_test.dart

 #library('DOMIsolatesTest');
 #import('../../lib/unittest/unittest.dart');
 #import('../../lib/unittest/html_config.dart');
 #import('dart:html');
 #import('dart:isolate');
 
 isolateMain(port) {
   port.receive((msg, replyTo) {
     if (msg != 'check') {
       replyTo.send('wrong msg: $msg');
@@ skipping 35 matching lines @@
     spawnDomIsolate(iframe.contentWindow, 'isolateMainTrampoline').then(
       expectAsync1((sendPort) {
         sendPort.call('check').then(
           expectAsync1((msg) {
             Expect.equals('about:blank', msg);
           }));
       }));
   });
 
   test('Null as target window', () {
-    expectThrow(() => spawnDomIsolate(null, 'isolateMain'));
+    expect(() => spawnDomIsolate(null, 'isolateMain'), throws);
   });
 
   test('Not window as target window', () {
-    expectThrow(() => spawnDomIsolate(document, 'isolateMain'));
+    expect(() => spawnDomIsolate(document, 'isolateMain'), throws);
   });
 }