Make subtype test stubs isolate-specific.

runtime/vm/assembler_arm64.cc

 // Copyright (c) 2014, 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"
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/longjump.h"
@@ skipping 1075 matching lines @@
   ASSERT(RawObject::kClassIdTagSize == 16);
   const intptr_t class_id_offset = Object::tags_offset() +
       RawObject::kClassIdTagPos / kBitsPerByte;
   LoadFromOffset(result, object, class_id_offset - kHeapObjectTag, pp,
                  kUnsignedHalfword);
 }
 
 
 void Assembler::LoadClassById(Register result, Register class_id, Register pp) {
   ASSERT(result != class_id);
-  LoadFieldFromOffset(result, CTX, Context::isolate_offset(), pp);
-  const intptr_t table_offset_in_isolate =
-      Isolate::class_table_offset() + ClassTable::table_offset();
-  LoadFromOffset(result, result, table_offset_in_isolate, pp);
+  LoadImmediate(result, Isolate::Current()->class_table()->TableAddress(), pp);
+  LoadFromOffset(result, result, 0, pp);
   ldr(result, Address(result, class_id, UXTX, Address::Scaled));
 }
 
 
 void Assembler::LoadClass(Register result, Register object, Register pp) {
   ASSERT(object != TMP);
   LoadClassId(TMP, object, pp);
   LoadClassById(result, TMP, pp);
 }
 
@@ skipping 409 matching lines @@
     add(base, array, Operand(index, LSL, shift));
   }
   const OperandSize size = Address::OperandSizeFor(cid);
   ASSERT(Address::CanHoldOffset(offset, Address::Offset, size));
   return Address(base, offset, Address::Offset, size);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64