Fix test and set/release of InnoDB mutex lock_word

likely due to missing a memory barrier, this was using test and set rather
than sync lock release. Also add memory barrier in for get lock word.

Index: mysql-5.6.17/storage/innobase/include/sync0sync.ic
===================================================================
--- mysql-5.6.17.orig/storage/innobase/include/sync0sync.ic
+++ mysql-5.6.17/storage/innobase/include/sync0sync.ic
@@ -80,7 +80,7 @@ ib_mutex_test_and_set(
 	ib_mutex_t*	mutex)	/*!< in: mutex */
 {
 #if defined(HAVE_ATOMIC_BUILTINS)
-	return(os_atomic_test_and_set_byte(&mutex->lock_word, 1));
+	return(__sync_lock_test_and_set(&mutex->lock_word, 1));
 #else
 	ibool	ret;
 
@@ -112,7 +112,7 @@ mutex_reset_lock_word(
 	/* In theory __sync_lock_release should be used to release the lock.
 	Unfortunately, it does not work properly alone. The workaround is
 	that more conservative __sync_lock_test_and_set is used instead. */
-	os_atomic_test_and_set_byte(&mutex->lock_word, 0);
+	__sync_lock_release(&mutex->lock_word);
 #else
 	mutex->lock_word = 0;
 
@@ -130,6 +130,7 @@ mutex_get_lock_word(
 {
 	ut_ad(mutex);
 
+	os_rmb;
 	return(mutex->lock_word);
 }