Fixes a bug in CheckClassInstr on arm64.

runtime/vm/assembler_arm64.h

 // 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.
 
 #ifndef VM_ASSEMBLER_ARM64_H_
 #define VM_ASSEMBLER_ARM64_H_
 
 #ifndef VM_ASSEMBLER_H_
 #error Do not include assembler_arm64.h directly; use assembler.h instead.
 #endif
@@ skipping 984 matching lines @@
     ldr(PP, Address(SP, 1 * kWordSize, Address::PostIndex));
     sub(PP, PP, Operand(kHeapObjectTag));
   }
   void tst(Register rn, Operand o) {
     ands(ZR, rn, o);
   }
   void tsti(Register rn, uint64_t imm) {
     andis(ZR, rn, imm);
   }
 
-  void Lsl(Register rd, Register rn, int shift) {
+  void LslImmediate(Register rd, Register rn, int shift) {
     add(rd, ZR, Operand(rn, LSL, shift));
   }
-  void Lslw(Register rd, Register rn, int shift) {
-    addw(rd, ZR, Operand(rn, LSL, shift));
-  }
-  void Lsr(Register rd, Register rn, int shift) {
+  void LsrImmediate(Register rd, Register rn, int shift) {
     add(rd, ZR, Operand(rn, LSR, shift));
   }
-  void Lsrw(Register rd, Register rn, int shift) {
-    ASSERT((shift >= 0) && (shift < 32));
-    addw(rd, ZR, Operand(rn, LSR, shift));
-  }
-  void Asr(Register rd, Register rn, int shift) {
+  void AsrImmediate(Register rd, Register rn, int shift) {
     add(rd, ZR, Operand(rn, ASR, shift));
   }
 
   void VRecps(VRegister vd, VRegister vn);
   void VRSqrts(VRegister vd, VRegister vn);
 
   void SmiUntag(Register reg) {
-    Asr(reg, reg, kSmiTagSize);
+    AsrImmediate(reg, reg, kSmiTagSize);
   }
   void SmiUntag(Register dst, Register src) {
-    Asr(dst, src, kSmiTagSize);
+    AsrImmediate(dst, src, kSmiTagSize);
   }
   void SmiTag(Register reg) {
-    Lsl(reg, reg, kSmiTagSize);
+    LslImmediate(reg, reg, kSmiTagSize);
   }
 
   // Branching to ExternalLabels.
   void Branch(const ExternalLabel* label, Register pp) {
     LoadExternalLabel(TMP, label, kNotPatchable, pp);
     br(TMP);
   }
 
   // Fixed length branch to label.
   void BranchPatchable(const ExternalLabel* label) {
@@ skipping 665 matching lines @@
                                   Register value,
                                   Label* no_update);
 
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(Assembler);
 };
 
 }  // namespace dart
 
 #endif  // VM_ASSEMBLER_ARM64_H_