Turn the NumberToStringStub into a hydrogen stub.

src/arm/full-codegen-arm.cc

Index: src/arm/full-codegen-arm.cc
diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
index 195fc8c5be7f6ae4bf5282ea6479755378ff5d9c..df42a7585110f898f007b400d21d07d7be519473 100644
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -3590,8 +3590,8 @@ void FullCodeGenerator::EmitSetValueOf(CallRuntime* expr) {
 void FullCodeGenerator::EmitNumberToString(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   ASSERT_EQ(args->length(), 1);
-  // Load the argument on the stack and call the stub.
-  VisitForStackValue(args->at(0));
+  // Load the argument into r0 and call the stub.
+  VisitForAccumulatorValue(args->at(0));
 
   NumberToStringStub stub;
   __ CallStub(&stub);