Track JS allocations as they arrive with no affection on performance when tracking is switched off

src/spaces.h

Index: src/spaces.h
diff --git a/src/spaces.h b/src/spaces.h
index 43f44a5c707d0c41632215943f2a553296a0f611..04af0313a3713dc2a8f059a4e072ffdea74ff29e 100644
--- a/src/spaces.h
+++ b/src/spaces.h
@@ -1717,6 +1717,8 @@ class PagedSpace : public Space {
   // Allocate the requested number of bytes in the space if possible, return a
   // failure object if not.
   MUST_USE_RESULT inline MaybeObject* AllocateRaw(int size_in_bytes);
+  MUST_USE_RESULT inline MaybeObject* AllocateRawForMigration(
+      int size_in_bytes);
 
   virtual bool ReserveSpace(int bytes);
 
@@ -1897,6 +1899,9 @@ class PagedSpace : public Space {
 
   friend class PageIterator;
   friend class SweeperThread;
+
+ private:
+  inline HeapObject* AllocateRawHelper(int size_in_bytes);
 };