[runtime] Cleanup DescriptorArray interface, remove more PropertyType usages.

src/property-descriptor.cc

Index: src/property-descriptor.cc
diff --git a/src/property-descriptor.cc b/src/property-descriptor.cc
index f1e7cade68a49ec7a181c38cef0593be0adec622..70ddd5d5217e5fc78d5c8b7324cb52e8e70d1061 100644
--- a/src/property-descriptor.cc
+++ b/src/property-descriptor.cc
@@ -75,7 +75,7 @@ bool ToPropertyDescriptorFastPath(Isolate* isolate, Handle<JSReceiver> obj,
     } else {
       DCHECK_EQ(kDescriptor, details.location());
       if (details.kind() == kData) {
-        value = handle(descs->GetConstant(i), isolate);
+        value = handle(descs->GetValue(i), isolate);
       } else {
         DCHECK_EQ(kAccessor, details.kind());
         // Bail out to slow path.