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

tests/corelib/future_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.
 
 // Tests for Future.immediate
 
 testImmediate() {
   final future = new Future<String>.immediate("42");
   Expect.isTrue(future.isComplete);
   Expect.isTrue(future.hasValue);
@@ skipping 291 matching lines @@
   Expect.throws(() { future.then((e) { }); });
   Expect.equals(ex, ex2);
 }
 
 // Tests for accessing the exception call stack.
 
 testCallStackThrowsIfNotComplete() {
   var exception;
   try {
     new Completer().future.stackTrace;
-  } catch (var ex) {
+  } catch (ex) {
     exception = ex;
   }
 
   Expect.isTrue(exception is FutureNotCompleteException);
 }
 
 testCallStackIsNullIfCompletedSuccessfully() {
   Expect.isNull(new Future.immediate('blah').stackTrace);
 }
 
@@ skipping 204 matching lines @@
   testExceptionWithCompletionAndSuccessHandlers();
   testExceptionWithCompletionAndSuccessAndExceptionHandlers();
   testTransformSuccess();
   testTransformFutureFails();
   testTransformTransformerFails();
   testChainSuccess();
   testChainFirstFutureFails();
   testChainTransformerFails();
   testChainSecondFutureFails();
 }