Revert "- Use a hash table to canonicalize instances/arrays to avoid having to iterate over a linea…

runtime/vm/snapshot.cc

Index: runtime/vm/snapshot.cc
diff --git a/runtime/vm/snapshot.cc b/runtime/vm/snapshot.cc
index 08e12dbb30a82e929873d2a4eb45f09ee15d5eae..c455d302f77a326acf8774258d02db40eab8c49c 100644
--- a/runtime/vm/snapshot.cc
+++ b/runtime/vm/snapshot.cc
@@ -542,7 +542,7 @@ RawObject* SnapshotReader::ReadInstance(intptr_t object_id,
       if (kind_ == Snapshot::kFull) {
         result->SetCanonical();
       } else {
-        *result = result->CheckAndCanonicalize(thread(), NULL);
+        *result = result->CheckAndCanonicalize(NULL);
         ASSERT(!result->IsNull());
       }
     }