Reland r21442 "Inobject slack tracking is done on a per-closure basis instead of per-shared info ba…

src/heap-snapshot-generator.cc

Index: src/heap-snapshot-generator.cc
diff --git a/src/heap-snapshot-generator.cc b/src/heap-snapshot-generator.cc
index fb1fa385069f6d03be019ddf17b1e1375ead59ac..652e3942a6874c9e2dbe46f689fb761ff7540a22 100644
--- a/src/heap-snapshot-generator.cc
+++ b/src/heap-snapshot-generator.cc
@@ -1421,9 +1421,6 @@ void V8HeapExplorer::ExtractSharedFunctionInfoReferences(
   SetInternalReference(obj, entry,
                        "feedback_vector", shared->feedback_vector(),
                        SharedFunctionInfo::kFeedbackVectorOffset);
-  SetWeakReference(obj, entry,
-                   "initial_map", shared->initial_map(),
-                   SharedFunctionInfo::kInitialMapOffset);
 }