Move atomic ops and related files to base library

src/base/atomicops_internals_arm64_gcc.h

 // Copyright 2012 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.
 
 // This file is an internal atomic implementation, use atomicops.h instead.
 
-#ifndef V8_ATOMICOPS_INTERNALS_ARM_GCC_H_
-#define V8_ATOMICOPS_INTERNALS_ARM_GCC_H_
+#ifndef V8_BASE_ATOMICOPS_INTERNALS_ARM_GCC_H_
+#define V8_BASE_ATOMICOPS_INTERNALS_ARM_GCC_H_
 
 namespace v8 {
-namespace internal {
+namespace base {
 
 inline void MemoryBarrier() {
   __asm__ __volatile__ ("dmb ish" ::: "memory");  // NOLINT
 }
 
 // NoBarrier versions of the operation include "memory" in the clobber list.
 // This is not required for direct usage of the NoBarrier versions of the
 // operations. However this is required for correctness when they are used as
 // part of the Acquire or Release versions, to ensure that nothing from outside
 // the call is reordered between the operation and the memory barrier. This does
@@ skipping 282 matching lines @@
   );  // NOLINT
 
   return value;
 }
 
 inline Atomic64 Release_Load(volatile const Atomic64* ptr) {
   MemoryBarrier();
   return *ptr;
 }
 
-} }  // namespace v8::internal
+} }  // namespace v8::base
 
-#endif  // V8_ATOMICOPS_INTERNALS_ARM_GCC_H_
+#endif  // V8_BASE_ATOMICOPS_INTERNALS_ARM_GCC_H_