Delete HAbnormalExit. It does more harm than good.

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 5388 matching lines @@
   // We don't optimize functions with invalid left-hand sides in
   // assignments, count operations, or for-in.  Consequently throw can
   // currently only occur in an effect context.
   ASSERT(ast_context()->IsEffect());
   CHECK_ALIVE(VisitForValue(expr->exception()));
 
   HValue* value = environment()->Pop();
   HThrow* instr = Add<HThrow>(value);
   instr->set_position(expr->position());
   Add<HSimulate>(expr->id());
-  current_block()->FinishExit(new(zone()) HAbnormalExit);
-  set_current_block(NULL);
 }
 
 
 HLoadNamedField* HGraphBuilder::BuildLoadNamedField(HValue* object,
                                                     HObjectAccess access) {
   if (FLAG_track_double_fields && access.representation().IsDouble()) {
     // load the heap number
     HLoadNamedField* heap_number = Add<HLoadNamedField>(
         object, access.WithRepresentation(Representation::Tagged()));
     heap_number->set_type(HType::HeapNumber());
@@ skipping 4464 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal