Fix the SRW_LOCK_DUMMY build with PLUGIN_PERFSCHEMA=NO

srw_lock_low: Declare the member functions public when wrapping rw_lock_t

storage/innobase/include/srw_lock.h

@@ -121,6 +121,7 @@ class srw_lock_low
   void wr_unlock() { ReleaseSRWLockExclusive(&lock); }
 # else
   rw_lock_t lock;
+public:
   void init() { my_rwlock_init(&lock, nullptr); }
   void destroy() { rwlock_destroy(&lock); }
   void rd_lock() { rw_rdlock(&lock); }