Rename IS_SPEC_OBJECT macro to IS_RECEIVER.

src/js/collection.js

Index: src/js/collection.js
diff --git a/src/js/collection.js b/src/js/collection.js
index 2b3f1aad71cfa8f055392929501fc0aaea9499c4..10d8a385e52b5643972dad0252a9fcc0b855c907 100644
--- a/src/js/collection.js
+++ b/src/js/collection.js
@@ -100,7 +100,7 @@ function GetExistingHash(key) {
     if ((field & 1 /* Name::kHashNotComputedMask */) === 0) {
       return field >>> 2 /* Name::kHashShift */;
     }
-  } else if (IS_SPEC_OBJECT(key) && !%_IsJSProxy(key) && !IS_GLOBAL(key)) {
+  } else if (IS_RECEIVER(key) && !%_IsJSProxy(key) && !IS_GLOBAL(key)) {
     var hash = GET_PRIVATE(key, hashCodeSymbol);
     return hash;
   }
@@ -294,7 +294,7 @@ function MapConstructor(iterable) {
     }
 
     for (var nextItem of iterable) {
-      if (!IS_SPEC_OBJECT(nextItem)) {
+      if (!IS_RECEIVER(nextItem)) {
         throw MakeTypeError(kIteratorValueNotAnObject, nextItem);
       }
       %_Call(adder, this, nextItem[0], nextItem[1]);