Change test to use const variables instead of macros

This is C++ so there's no reason to use macros here.

	* testsuite/29_atomics/atomic_flag/test_and_set/explicit-hle.cc: Use
	const variables instead of macros.

From-SVN: r269585

libstdc++-v3/ChangeLog

 2019-03-11  Jonathan Wakely  <jwakely@redhat.com>
 
+	* testsuite/29_atomics/atomic_flag/test_and_set/explicit-hle.cc: Use
+	const variables instead of macros.
+
 	PR libstdc++/89629
 	* libsupc++/hash_bytes.cc [__SIZEOF_SIZE_T__ == 8] (_Hash_bytes):
 	Use correct type for len_aligned.

libstdc++-v3/testsuite/29_atomics/atomic_flag/test_and_set/explicit-hle.cc

@@ -25,8 +25,8 @@
 
 #include <atomic>
 
-#define ACQ memory_order_acquire | __memory_order_hle_acquire
-#define REL memory_order_release | __memory_order_hle_release
+const auto ACQ = std::memory_order_acquire | std::__memory_order_hle_acquire;
+const auto REL = std::memory_order_release | std::__memory_order_hle_release;
 
 int main()
 {