Update corelib/ and lib/ to use the new try-catch syntax.

lib/compiler/implementation/dart2js.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.
 
 #library('dart2js');
 
 #import('dart:io');
 #import('dart:uri');
 #import('dart:utf');
 
@@ skipping 143 matching lines @@
   Map<String, SourceFile> sourceFiles = <String, SourceFile>{};
   int dartBytesRead = 0;
 
   Future<String> provider(Uri uri) {
     if (uri.scheme != 'file') {
       throw new IllegalArgumentException(uri);
     }
     String source;
     try {
       source = readAll(uriPathToNative(uri.path));
-    } catch (FileIOException ex) {
+    } on FileIOException catch (ex) {
       throw 'Error: Cannot read "${relativize(cwd, uri)}" (${ex.osError}).';
     }
     dartBytesRead += source.length;
     sourceFiles[uri.toString()] =
       new SourceFile(relativize(cwd, uri), source);
     return new Future.immediate(source);
   }
 
   void info(var message, [api.Diagnostic kind = api.Diagnostic.VERBOSE_INFO]) {
     if (!verbose && kind === api.Diagnostic.VERBOSE_INFO) return;
@@ skipping 186 matching lines @@
 
 void helpAndFail(String message) {
   help();
   print('');
   fail(message);
 }
 
 void main() {
   try {
     compilerMain(new Options());
-  } catch (var exception, var trace) {
+  } catch (exception, trace) {
     try {
       print('Internal error: $exception');
-    } catch (var ignored) {
+    } catch (ignored) {
       print('Internal error: error while printing exception');
     }
     try {
       print(trace);
     } finally {
       exit(253); // 253 is recognized as a crash by our test scripts.
     }
   }
 }