Simplify, speed-up correct-context ObjectObserve calls

src/object-observe.js

Index: src/object-observe.js
diff --git a/src/object-observe.js b/src/object-observe.js
index 03afd3f366b5b41b8a20e3c0d2e729dfa934e2cf..2dfc7522f77ab6db88baf125a0be4ab3707d8092 100644
--- a/src/object-observe.js
+++ b/src/object-observe.js
@@ -368,7 +368,8 @@ function ObjectObserve(object, callback, acceptList) {
   if (ObjectIsFrozen(callback))
     throw MakeTypeError("observe_callback_frozen");
 
-  return %ObjectObserveInObjectContext(object, callback, acceptList);
+  var objectObserveFn = %GetObjectContextObjectObserve(object);
+  return objectObserveFn(object, callback, acceptList);
 }
 
 function NativeObjectObserve(object, callback, acceptList) {
@@ -543,8 +544,8 @@ function ObjectNotifierPerformChange(changeType, changeFn) {
   if (!IS_SPEC_FUNCTION(changeFn))
     throw MakeTypeError("observe_perform_non_function");
 
-  return %ObjectNotifierPerformChangeInObjectContext(
-      objectInfo, changeType, changeFn);
+  var performChangeFn = %GetObjectContextNotifierPerformChange(objectInfo);
+  performChangeFn(objectInfo, changeType, changeFn);
 }
 
 function NativeObjectNotifierPerformChange(objectInfo, changeType, changeFn) {
@@ -571,7 +572,8 @@ function ObjectGetNotifier(object) {
 
   if (!%ObjectWasCreatedInCurrentOrigin(object)) return null;
 
-  return %ObjectGetNotifierInObjectContext(object);
+  var getNotifierFn = %GetObjectContextObjectGetNotifier(object);
+  return getNotifierFn(object);
 }
 
 function NativeObjectGetNotifier(object) {