Fixed issue in MallocHooks where a MallocHookScope was accidentally removed during a merge, causing…

runtime/vm/hash_map.h

Index: runtime/vm/hash_map.h
diff --git a/runtime/vm/hash_map.h b/runtime/vm/hash_map.h
index 6526acaf5c6b81f5c065e78ca06a10ceea543c2f..c9eb941c9a13bcb1bcc26326c57bb6ea4fc7907f 100644
--- a/runtime/vm/hash_map.h
+++ b/runtime/vm/hash_map.h
@@ -27,7 +27,7 @@ class BaseDirectChainedHashMap : public B {
 
   BaseDirectChainedHashMap(const BaseDirectChainedHashMap& other);
 
-  ~BaseDirectChainedHashMap() {
+  virtual ~BaseDirectChainedHashMap() {
     allocator_->template Free<HashMapListElement>(array_, array_size_);
     allocator_->template Free<HashMapListElement>(lists_, lists_size_);
   }
@@ -42,7 +42,7 @@ class BaseDirectChainedHashMap : public B {
 
   bool IsEmpty() const { return count_ == 0; }
 
-  void Clear() {
+  virtual void Clear() {
     if (!IsEmpty()) {
       count_ = 0;
       InitArray(array_, array_size_);