Make subtype test cache stub shared between isolates.

runtime/vm/assembler_mips.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // NOLINT
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/assembler.h"
 #include "vm/longjump.h"
 #include "vm/runtime_entry.h"
@@ skipping 652 matching lines @@
   ASSERT(RawObject::kClassIdTagSize == 16);
   const intptr_t class_id_offset = Object::tags_offset() +
       RawObject::kClassIdTagPos / kBitsPerByte;
   lhu(result, FieldAddress(object, class_id_offset));
 }
 
 
 void Assembler::LoadClassById(Register result, Register class_id) {
   ASSERT(!in_delay_slot_);
   ASSERT(result != class_id);
-  LoadImmediate(result, Isolate::Current()->class_table()->TableAddress());
-  lw(result, Address(result, 0));
+  LoadIsolate(result);
+  const intptr_t offset =
+      Isolate::class_table_offset() + ClassTable::table_offset();
+  lw(result, Address(result, offset));
   sll(TMP, class_id, 2);
   addu(result, result, TMP);
   lw(result, Address(result));
 }
 
 
 void Assembler::LoadClass(Register result, Register object) {
   ASSERT(!in_delay_slot_);
   ASSERT(TMP != result);
   LoadClassId(TMP, object);
@@ skipping 592 matching lines @@
   Label stop;
   b(&stop);
   Emit(reinterpret_cast<int32_t>(message));
   Bind(&stop);
   break_(Instr::kStopMessageCode);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS