Remove the rest_parameter(int*) variant, use rest_parameter() instead.

src/crankshaft/hydrogen.cc

Index: src/crankshaft/hydrogen.cc
diff --git a/src/crankshaft/hydrogen.cc b/src/crankshaft/hydrogen.cc
index 240101eeebdb377c24e2963efb15410af7284ce4..95f2d7a153e885a20b6c954c565df4fc5dc792d5 100644
--- a/src/crankshaft/hydrogen.cc
+++ b/src/crankshaft/hydrogen.cc
@@ -4651,9 +4651,7 @@ void HOptimizedGraphBuilder::SetUpScope(DeclarationScope* scope) {
     environment()->Bind(scope->arguments(), arguments_object);
   }
 
-  int rest_index;
-  Variable* rest = scope->rest_parameter(&rest_index);
-  if (rest) {
+  if (scope->rest_parameter() != nullptr) {
     return Bailout(kRestParameter);
   }
 
@@ -8406,9 +8404,7 @@ bool HOptimizedGraphBuilder::TryInline(Handle<JSFunction> target,
     return false;
   }
 
-  int rest_index;
-  Variable* rest = target_info.scope()->rest_parameter(&rest_index);
-  if (rest) {
+  if (target_info.scope()->rest_parameter() != nullptr) {
     TraceInline(target, caller, "target uses rest parameters");
     return false;
   }