Revert "Added ability to request zone memory information for all isolates through the VM service an…

runtime/observatory/lib/src/models/objects/isolate.dart

Index: runtime/observatory/lib/src/models/objects/isolate.dart
diff --git a/runtime/observatory/lib/src/models/objects/isolate.dart b/runtime/observatory/lib/src/models/objects/isolate.dart
index 8cc5c79595548bc8abda9071b39484360cf08eb0..f114941ad840532bf4582412f7e654ad94daebc5 100644
--- a/runtime/observatory/lib/src/models/objects/isolate.dart
+++ b/runtime/observatory/lib/src/models/objects/isolate.dart
@@ -51,9 +51,6 @@ abstract class Isolate extends IsolateRef {
   /// [optional] The error that is causing this isolate to exit, if applicable.
   Error get error;
 
-  /// The list of threads associated with this isolate.
-  Iterable<Thread> get threads;
-
   /// The current pause on exception mode for this isolate.
   //ExceptionPauseMode get exceptionPauseMode;