Deoptimizer support for hydrogen stubs that accept a variable number of arguments.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 823fea942ecf5ed8e8294e7ebd02e4320efef06c..b1787db2dd66359e978a84045cc9baaf1e86edac 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -4433,6 +4433,14 @@ class HParameter: public HTemplateInstruction<0> {
     set_representation(Representation::Tagged());
   }
 
+  explicit HParameter(unsigned index,
+                      ParameterKind kind,
+                      Representation r)
+      : index_(index),
+        kind_(kind) {
+    set_representation(r);
+  }
+
   unsigned index() const { return index_; }
   ParameterKind kind() const { return kind_; }