Update V8 to r6101 as required by WebKit r74534

Change-Id: I7f84af8dd732f11898fd644b2c2b1538914cb78d
diff --git a/src/variables.cc b/src/variables.cc
index 504e224..c1440b7 100644
--- a/src/variables.cc
+++ b/src/variables.cc
@@ -86,6 +86,18 @@
 }
 
 
+bool Variable::IsParameter() const {
+  Slot* s = AsSlot();
+  return s != NULL && s->type() == Slot::PARAMETER;
+}
+
+
+bool Variable::IsStackLocal() const {
+  Slot* s = AsSlot();
+  return s != NULL && s->type() == Slot::LOCAL;
+}
+
+
 Variable::Variable(Scope* scope,
                    Handle<String> name,
                    Mode mode,