core: Record change in size after defrag

For JSON type, after defrag size may change. The page usage object
carries this change out to a higher call level where the db stats can be
updated.

Signed-off-by: Abhijat Malviya <[email protected]>

Author: abhijat

src/core/page_usage_stats.h

@@ -93,6 +93,7 @@ class PageUsage {
 
   // For use in testing, forces reallocate check to always return true
   bool force_reallocate_{false};
+
 };
 
 }  // namespace dfly