Revert Dart_PropagateError until I can track down the problems in

runtime/vm/code_generator_x64.cc

 // 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.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/code_generator.h"
 
 #include "lib/error.h"
@@ skipping 173 matching lines @@
                              const ParsedFunction& parsed_function)
     : assembler_(assembler),
       parsed_function_(parsed_function),
       locals_space_size_(-1),
       state_(NULL),
       pc_descriptors_list_(NULL),
       exception_handlers_list_(NULL),
       try_index_(CatchClauseNode::kInvalidTryIndex) {
   ASSERT(assembler_ != NULL);
   ASSERT(parsed_function.node_sequence() != NULL);
-  ASSERT(Isolate::Current()->long_jump_base()->IsSafeToJump());
   pc_descriptors_list_ = new CodeGenerator::DescriptorList();
   exception_handlers_list_ = new CodeGenerator::HandlerList();
 }
 
 
 bool CodeGenerator::IsResultNeeded(AstNode* node) const {
   return !state()->IsRootNode(node);
 }
 
 
@@ skipping 2589 matching lines @@
   const Error& error = Error::Handle(
       Parser::FormatError(script, token_index, "Error", format, args));
   va_end(args);
   Isolate::Current()->long_jump_base()->Jump(1, error);
   UNREACHABLE();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64