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

tests/compiler/dart2js_foreign/native_checked_fields_test.dart

 // Copyright (c) 2011, 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.
 
 // Test that type checks occur on assignment to fields of native methods.
 
 @native("*A")
 class A  {
   int foo;
 }
@@ skipping 13 matching lines @@
 
 makeA = function(){return new A;};
 makeB = function(){return new B;};
 """)
 void setup();
 
 expectThrows(action()) {
   bool threw = false;
   try {
     action();
-  } catch (var e) {
+  } catch (e) {
     threw = true;
   }
   Expect.isTrue(threw);
 }
 
 checkedModeTest() {
   var things = [makeA(), makeB()];
   var a = things[0];
   var b = things[1];
 
@@ skipping 48 matching lines @@
   Expect.equals(b.foo, 124);
 }
 
 bool isCheckedMode() {
   var stuff = [1, 'string'];
   var a = stuff[0];
   // Checked-mode detection.
   try {
     String s = a;
     return false;
-  } catch (var e) { }
+  } catch (e) {
+    // Ignore.
+  }
   return true;
 }
 
 main() {
   setup();
 
   if (isCheckedMode()) {
     checkedModeTest();
   } else {
     uncheckedModeTest();
   }
 }