Implement try/catch without finally, and without type checks.

frog/leg/compiler.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.
 
 class WorkItem {
   final Element element;
   TreeElements resolutionTree;
   Function run;
   Map<int, BailoutInfo> bailouts = null;
+  bool allowSpeculativeOptimization = true;
 
   WorkItem.toCompile(this.element) : resolutionTree = null {
     run = this.compile;
   }
 
   WorkItem.toCodegen(this.element, this.resolutionTree) {
     run = this.codegen;
   }
 
   WorkItem.bailoutVersion(this.element, this.resolutionTree, this.bailouts) {
@@ skipping 318 matching lines @@
 
 class CompilerCancelledException implements Exception {
   final String reason;
   CompilerCancelledException(this.reason);
 
   String toString() {
     String banner = 'compiler cancelled';
     return (reason !== null) ? '$banner: $reason' : '$banner';
   }
 }