Update almost all tests (except co19) to use the new try-catch syntax.

tests/standalone/io/http_read_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.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
 
 #import("dart:isolate");
@@ skipping 111 matching lines @@
 
   void dispatch(message, SendPort replyTo) {
     if (message.isStart) {
       _server = new HttpServer();
       try {
         _server.listen("127.0.0.1", 0);
         _server.defaultRequestHandler = (HttpRequest req, HttpResponse rsp) {
           _requestReceivedHandler(req, rsp);
         };
         replyTo.send(new TestServerStatus.started(_server.port), null);
-      } catch (var e) {
+      } catch (e) {
         replyTo.send(new TestServerStatus.error(), null);
       }
     } else if (message.isStop) {
       _server.close();
       port.close();
       replyTo.send(new TestServerStatus.stopped(), null);
     } else if (message.isChunkedEncoding) {
       _chunkedEncoding = true;
     }
   }
@@ skipping 118 matching lines @@
   }
   testServerMain.start();
 }
 
 void main() {
   testReadInto(true);
   testReadInto(false);
   testReadShort(true);
   testReadShort(false);
 }