Optimize the typeof operator.

src/arm64/interface-descriptors-arm64.cc

Index: src/arm64/interface-descriptors-arm64.cc
diff --git a/src/arm64/interface-descriptors-arm64.cc b/src/arm64/interface-descriptors-arm64.cc
index 7dff69c85a07c6e34af8c2f8b258738655c33310..77872241568ce49d0dd3b1a64793d3ea1466912b 100644
--- a/src/arm64/interface-descriptors-arm64.cc
+++ b/src/arm64/interface-descriptors-arm64.cc
@@ -97,6 +97,12 @@ void NumberToStringDescriptor::Initialize(CallInterfaceDescriptorData* data) {
 }
 
 
+void TypeofDescriptor::Initialize(CallInterfaceDescriptorData* data) {
+  Register registers[] = {cp, x3};
+  data->Initialize(arraysize(registers), registers, NULL);
+}
+
+
 void FastCloneShallowArrayDescriptor::Initialize(
     CallInterfaceDescriptorData* data) {
   // cp: context