[es6] Fix missing bits for full @@toPrimitive support.

src/full-codegen/x64/full-codegen-x64.cc

Index: src/full-codegen/x64/full-codegen-x64.cc
diff --git a/src/full-codegen/x64/full-codegen-x64.cc b/src/full-codegen/x64/full-codegen-x64.cc
index 0133c09d6e7d78b618b095073c09f9e05d52cb42..254a7e21b5fca1d3547d5b514bc7c3447a01df30 100644
--- a/src/full-codegen/x64/full-codegen-x64.cc
+++ b/src/full-codegen/x64/full-codegen-x64.cc
@@ -3703,6 +3703,19 @@ void FullCodeGenerator::EmitToString(CallRuntime* expr) {
 }
 
 
+void FullCodeGenerator::EmitToNumber(CallRuntime* expr) {
+  ZoneList<Expression*>* args = expr->arguments();
+  DCHECK_EQ(1, args->length());
+
+  // Load the argument into rax and convert it.
+  VisitForAccumulatorValue(args->at(0));
+
+  ToNumberStub stub(isolate());
+  __ CallStub(&stub);
+  context()->Plug(rax);
+}
+
+
 void FullCodeGenerator::EmitToName(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK_EQ(1, args->length());