[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 6daee25c1390d0aa53cc09f67c81dedb5a776db6..aeb7262ab179a8326e872773cdde821b383a324c 100644
--- a/src/assembler.cc
+++ b/src/assembler.cc
@@ -1265,12 +1265,6 @@ 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());