Enable snapshots on MIPS. This is based on

src/arm/assembler-arm.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 667 matching lines @@
   // Return the address in the constant pool of the code target address used by
   // the branch/call instruction at pc.
   INLINE(static Address target_address_address_at(Address pc));
 
   // Read/Modify the code target address in the branch/call instruction at pc.
   INLINE(static Address target_address_at(Address pc));
   INLINE(static void set_target_address_at(Address pc, Address target));
 
   // This sets the branch destination (which is in the constant pool on ARM).
   // This is for calls and branches within generated code.
-  inline static void set_target_at(Address constant_pool_entry, Address target);
+  inline static void deserialization_set_special_target_at(
+      Address constant_pool_entry, Address target);
 
   // This sets the branch destination (which is in the constant pool on ARM).
   // This is for calls and branches to runtime code.
   inline static void set_external_target_at(Address constant_pool_entry,
-                                            Address target) {
-    set_target_at(constant_pool_entry, target);
-  }
+                                            Address target);
 
   // Here we are patching the address in the constant pool, not the actual call
   // instruction.  The address in the constant pool is the same size as a
   // pointer.
-  static const int kCallTargetSize = kPointerSize;
-  static const int kExternalTargetSize = kPointerSize;
+  static const int kSpecialTargetSize = kPointerSize;
 
   // Size of an instruction.
   static const int kInstrSize = sizeof(Instr);
 
   // Distance between the instruction referring to the address of the call
   // target and the return address.
 #ifdef USE_BLX
   // Call sequence is:
   //  ldr  ip, [pc, #...] @ call address
   //  blx  ip
@@ skipping 724 matching lines @@
  public:
   explicit EnsureSpace(Assembler* assembler) {
     assembler->CheckBuffer();
   }
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_ASSEMBLER_ARM_H_