[heap] Remove dead code from PagedSpace

src/heap/spaces.h

Index: src/heap/spaces.h
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
index 791ee6c32ac410b63ff4de43ab2d27eec113a4dd..15de063306b0c7efc4c1ce6535a321a7b222a563 100644
--- a/src/heap/spaces.h
+++ b/src/heap/spaces.h
@@ -2172,12 +2172,6 @@ class PagedSpace : public Space {
   static void ResetCodeStatistics(Isolate* isolate);
 #endif
 
-  // This function tries to steal size_in_bytes memory from the sweeper threads
-  // free-lists. If it does not succeed stealing enough memory, it will wait
-  // for the sweeper threads to finish sweeping.
-  // It returns true when sweeping is completed and false otherwise.
-  bool EnsureSweeperProgress(intptr_t size_in_bytes);
-
   Page* FirstPage() { return anchor_.next_page(); }
   Page* LastPage() { return anchor_.prev_page(); }