Restart AST node numbering when we enter a function.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 99e206bc8cac62193da4719e8229272dbc083a36..31ef7d9f83fbe9bc5ff3f4aace4e4ed3f488fabc 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -581,7 +581,7 @@ HGraph::HGraph(CompilationInfo* info)
       values_(16),
       phi_list_(NULL) {
   start_environment_ = new HEnvironment(NULL, info->scope(), info->closure());
-  start_environment_->set_ast_id(info->function()->id());
+  start_environment_->set_ast_id(0);
   entry_block_ = CreateBasicBlock();
   entry_block_->SetInitialEnvironment(start_environment_);
 }
@@ -2198,7 +2198,7 @@ HGraph* HGraphBuilder::CreateGraph() {
     HEnvironment* initial_env = environment()->CopyWithoutHistory();
     HBasicBlock* body_entry = CreateBasicBlock(initial_env);
     current_block()->Goto(body_entry);
-    body_entry->SetJoinId(info()->function()->id());
+    body_entry->SetJoinId(0);
     set_current_block(body_entry);
     VisitStatements(info()->function()->body());
     if (HasStackOverflow()) return NULL;