Revert "Modifies the debug garbage collector (CollectAllGarbage()) to correctly remove inter-genera…

runtime/vm/scavenger.h

Index: runtime/vm/scavenger.h
diff --git a/runtime/vm/scavenger.h b/runtime/vm/scavenger.h
index fd4663de7decf7680a9cd26dc3581d2af389e295..8d8c0e49e3fa121840f8d51ba958548d3c5401b9 100644
--- a/runtime/vm/scavenger.h
+++ b/runtime/vm/scavenger.h
@@ -149,7 +149,11 @@ class Scavenger {
   void Scavenge(bool invoke_api_callbacks);
 
   // Promote all live objects.
-  void Evacuate();
+  void Evacuate() {
+    Scavenge();
+    Scavenge();
+    ASSERT(UsedInWords() == 0);
+  }
 
   // Accessors to generate code for inlined allocation.
   uword* TopAddress() { return &top_; }
@@ -293,8 +297,6 @@ class Scavenger {
   // The total size of external data associated with objects in this scavenger.
   intptr_t external_size_;
 
-  bool failed_to_promote_;
-
   friend class ScavengerVisitor;
   friend class ScavengerWeakVisitor;