[heap] Move to page lookups for SemiSpace, NewSpace, and Heap containment methods

src/assembler.cc

Index: src/assembler.cc
diff --git a/src/assembler.cc b/src/assembler.cc
index 716566e2f705498c4fa97b0c3459c707538f6a4c..c40ae52327cbcc55c90190a69a179d465a6b8828 100644
--- a/src/assembler.cc
+++ b/src/assembler.cc
@@ -1270,12 +1270,6 @@ ExternalReference ExternalReference::store_buffer_top(Isolate* isolate) {
 }
 
 
-ExternalReference ExternalReference::new_space_mask(Isolate* isolate) {
-  return ExternalReference(reinterpret_cast<Address>(
-      isolate->heap()->NewSpaceMask()));
-}
-
-
 ExternalReference ExternalReference::new_space_allocation_top_address(
     Isolate* isolate) {
   return ExternalReference(isolate->heap()->NewSpaceAllocationTopAddress());