[sanitizer] Generalize atomic_uint8_t, atomic_uint16_t, ... into a template. NFC.

[delcypher]

LGTM.

[kubamracek]

This was reverted due to failure on Windows.

compiler-rt/lib/sanitizer_common/sanitizer_atomic.h

enum memory_order {
   memory_order_relaxed = 1 << 0,
   memory_order_consume = 1 << 1,
   memory_order_acquire = 1 << 2,
   memory_order_release = 1 << 3,
   memory_order_acq_rel = 1 << 4,
   memory_order_seq_cst = 1 << 5
 };
 
-struct atomic_uint8_t {
-  typedef u8 Type;
-  volatile Type val_dont_use;
-};
-
-struct atomic_uint16_t {
-  typedef u16 Type;
-  volatile Type val_dont_use;
-};
-
-struct atomic_sint32_t {
-  typedef s32 Type;
-  volatile Type val_dont_use;
-};
-
-struct atomic_uint32_t {
-  typedef u32 Type;
-  volatile Type val_dont_use;
-};
-
-struct atomic_uint64_t {
-  typedef u64 Type;
-  // On 32-bit platforms u64 is not necessary aligned on 8 bytes.
-  volatile ALIGNED(8) Type val_dont_use;
+template<typename T>
+struct atomic {
+  typedef T Type;
+  volatile Type ALIGNED(sizeof(Type)) val_dont_use;
 };
 
-struct atomic_uintptr_t {
-  typedef uptr Type;
-  volatile Type val_dont_use;
-};
+typedef atomic<u8> atomic_uint8_t;
+typedef atomic<u16> atomic_uint16_t;
+typedef atomic<s32> atomic_sint32_t;
+typedef atomic<u32> atomic_uint32_t;
+typedef atomic<u64> atomic_uint64_t;
+typedef atomic<uptr> atomic_uintptr_t;
 
 }  // namespace __sanitizer
 
 #if defined(__clang__) || defined(__GNUC__)
 # include "sanitizer_atomic_clang.h"
 #elif defined(_MSC_VER)
 # include "sanitizer_atomic_msvc.h"
 #else