Remove more dead code after Object.observe removal

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 37639ece53fa34dc45c532641ac23ab48c529984..13b197d2a8cb5adb85e6c6c766e24c5659e1481a 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -1115,8 +1115,20 @@ void Genesis::InitializeGlobal(Handle<JSGlobalObject> global_object,
         object_function, "keys", Builtins::kObjectKeys, 1, false);
     native_context()->set_object_keys(*object_keys);
 
+    SimpleInstallFunction(isolate->initial_object_prototype(),
+                          "__defineGetter__", Builtins::kObjectDefineGetter, 2,
+                          true);
+    SimpleInstallFunction(isolate->initial_object_prototype(),
+                          "__defineSetter__", Builtins::kObjectDefineSetter, 2,
+                          true);
     SimpleInstallFunction(isolate->initial_object_prototype(), "hasOwnProperty",
                           Builtins::kObjectHasOwnProperty, 1, true);
+    SimpleInstallFunction(isolate->initial_object_prototype(),
+                          "__lookupGetter__", Builtins::kObjectLookupGetter, 1,
+                          true);
+    SimpleInstallFunction(isolate->initial_object_prototype(),
+                          "__lookupSetter__", Builtins::kObjectLookupSetter, 1,
+                          true);
   }
 
   Handle<JSObject> global(native_context()->global_object());