After-merge fix

mysqld_exit(): Change the assertion failure on
global_status_var.global_memory_used == 0
to fprintf, like in 0bcb65d3

It appears that in some cases, that variable may be nonzero
even when LeakSanitizer (WITH_ASAN) would not report errors.
This was observed in 10.4 88cf6f1c
with the MDEV-22348 test case (Aria startup failure when running
main.default_storage_engine).

sql/mysqld.cc

@@ -2191,10 +2191,10 @@ static void mysqld_exit(int exit_code)
   set_malloc_size_cb(NULL);
   if (global_status_var.global_memory_used)
   {
-#ifdef SAFEMALLOC
-    sf_report_leaked_memory(0);
-#endif
-    DBUG_SLOW_ASSERT(global_status_var.global_memory_used == 0);
+    fprintf(stderr, "Warning: Memory not freed: %lld\n",
+            (longlong) global_status_var.global_memory_used);
+    if (exit_code == 0)
+      SAFEMALLOC_REPORT_MEMORY(0);
   }
   cleanup_tls();
   DBUG_LEAVE;