Fix rewriter to not treat throw as an expression.

src/rewriter.cc

Index: src/rewriter.cc
diff --git a/src/rewriter.cc b/src/rewriter.cc
index 55f93ee0d7165e40d65852671f7d92a4e0c99b47..e58ddb417e267763599dbf78dbc3c0f9f97ac0b4 100644
--- a/src/rewriter.cc
+++ b/src/rewriter.cc
@@ -111,7 +111,7 @@ void Processor::VisitBlock(Block* node) {
 
 void Processor::VisitExpressionStatement(ExpressionStatement* node) {
   // Rewrite : <x>; -> .result = <x>;
-  if (!is_set_) {
+  if (!is_set_ && !node->expression()->IsThrow()) {
     node->set_expression(SetResult(node->expression()));
     if (!in_try_) is_set_ = true;
   }