Optimize AOT's switchable calls for the monomorphic case.

runtime/vm/instructions_arm64_test.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/instructions.h"
 #include "vm/stub_code.h"
 #include "vm/unit_test.h"
 
 namespace dart {
 
 #define __ assembler->
 
 ASSEMBLER_TEST_GENERATE(Call, assembler) {
   // Code accessing pp is generated, but not executed. Uninitialized pp is OK.
   __ set_constant_pool_allowed(true);
   __ BranchLinkPatchable(*StubCode::InvokeDartCode_entry());
   __ ret();
 }
 
 
 ASSEMBLER_TEST_RUN(Call, test) {
   // The return address, which must be the address of an instruction contained
   // in the code, points to the Ret instruction above, i.e. one instruction
   // before the end of the code buffer.
-  CallPattern call(test->entry() + test->code().Size() - Instr::kInstrSize,
+  uword end = test->payload_start() + test->code().Size();
+  CallPattern call(end - Instr::kInstrSize,
                    test->code());
   EXPECT_EQ(StubCode::InvokeDartCode_entry()->code(),
             call.TargetCode());
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64