Remove usages of Heap::NewSpaceStart and its external reference

src/assembler.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 969 matching lines @@
   // Static variable RegExpStack::limit_address()
   static ExternalReference address_of_regexp_stack_limit(Isolate* isolate);
 
   // Static variables for RegExp.
   static ExternalReference address_of_static_offsets_vector(Isolate* isolate);
   static ExternalReference address_of_regexp_stack_memory_address(
       Isolate* isolate);
   static ExternalReference address_of_regexp_stack_memory_size(
       Isolate* isolate);
 
-  // Static variable Heap::NewSpaceStart()
-  static ExternalReference new_space_start(Isolate* isolate);
-
   // Write barrier.
   static ExternalReference store_buffer_top(Isolate* isolate);
 
   // Used for fast allocation in generated code.
   static ExternalReference new_space_allocation_top_address(Isolate* isolate);
   static ExternalReference new_space_allocation_limit_address(Isolate* isolate);
   static ExternalReference old_space_allocation_top_address(Isolate* isolate);
   static ExternalReference old_space_allocation_limit_address(Isolate* isolate);
 
   static ExternalReference mod_two_doubles_operation(Isolate* isolate);
@@ skipping 315 matching lines @@
     std::vector<ConstantPoolEntry> shared_entries;
   };
 
   Label emitted_label_;  // Records pc_offset of emitted pool
   PerTypeEntryInfo info_[ConstantPoolEntry::NUMBER_OF_TYPES];
 };
 
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_ASSEMBLER_H_