Revert of [Atomics] Implement ldaxr/stlxr instructions in ARM64 simulator

src/arm64/constants-arm64.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_ARM64_CONSTANTS_ARM64_H_
 #define V8_ARM64_CONSTANTS_ARM64_H_
 
 #include "src/base/macros.h"
 #include "src/globals.h"
 
@@ skipping 181 matching lines @@
   V_(ImmHint, 11, 5, Bits)                              \
   V_(ImmBarrierDomain, 11, 10, Bits)                    \
   V_(ImmBarrierType, 9, 8, Bits)                        \
                                                         \
   /* System (MRS, MSR) */                               \
   V_(ImmSystemRegister, 19, 5, Bits)                    \
   V_(SysO0, 19, 19, Bits)                               \
   V_(SysOp1, 18, 16, Bits)                              \
   V_(SysOp2, 7, 5, Bits)                                \
   V_(CRn, 15, 12, Bits)                                 \
-  V_(CRm, 11, 8, Bits)                                  \
-                                                        \
-  /* Load-/store-exclusive */                           \
-  V_(LoadStoreXLoad, 22, 22, Bits)                      \
-  V_(LoadStoreXNotExclusive, 23, 23, Bits)              \
-  V_(LoadStoreXAcquireRelease, 15, 15, Bits)            \
-  V_(LoadStoreXSizeLog2, 31, 30, Bits)                  \
-  V_(LoadStoreXPair, 21, 21, Bits)
+  V_(CRm, 11, 8, Bits)
 
 #define SYSTEM_REGISTER_FIELDS_LIST(V_, M_)                                    \
 /* NZCV */                                                                     \
 V_(Flags, 31, 28, Bits, uint32_t)                                              \
 V_(N,     31, 31, Bits, bool)                                                  \
 V_(Z,     30, 30, Bits, bool)                                                  \
 V_(C,     29, 29, Bits, bool)                                                  \
 V_(V,     28, 28, Bits, uint32_t)                                              \
 M_(NZCV, Flags_mask)                                                           \
                                                                                \
@@ skipping 1037 matching lines @@
 
 enum UnallocatedOp {
   UnallocatedFixed = 0x00000000,
   UnallocatedFMask = 0x00000000
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ARM64_CONSTANTS_ARM64_H_