Revert of Changed scavenge GC to collect unmodified references

src/global-handles.h

Index: src/global-handles.h
diff --git a/src/global-handles.h b/src/global-handles.h
index c321f2c269e448705b98a67e3160248d1820f1f6..63c1760796e90cd7b3d118f0dab77a1ff1ef0b00 100644
--- a/src/global-handles.h
+++ b/src/global-handles.h
@@ -204,7 +204,7 @@
   // them as pending.
   void IdentifyWeakHandles(WeakSlotCallback f);
 
-  // NOTE: Five ...NewSpace... functions below are used during
+  // NOTE: Three ...NewSpace... functions below are used during
   // scavenge collections and iterate over sets of handles that are
   // guaranteed to contain all handles holding new space objects (but
   // may also include old space objects).
@@ -219,19 +219,6 @@
   // Iterates over weak independent or partially independent handles.
   // See the note above.
   void IterateNewSpaceWeakIndependentRoots(ObjectVisitor* v);
-
-  // Finds weak independent or unmodified handles satisfying
-  // the callback predicate and marks them as pending. See the note above.
-  void MarkNewSpaceWeakUnmodifiedObjectsPending(
-      WeakSlotCallbackWithHeap is_unscavenged);
-
-  // Iterates over weak independent or unmodified handles.
-  // See the note above.
-  void IterateNewSpaceWeakUnmodifiedRoots(ObjectVisitor* v);
-
-  // Identify unmodified objects that are in weak state and marks them
-  // unmodified
-  void IdentifyWeakUnmodifiedObjects(WeakSlotCallback is_unmodified);
 
   // Iterate over objects in object groups that have at least one object
   // which requires visiting. The callback has to return true if objects