Fix for BUG#41102 "Maria: maria-no-logging.test fails randomly on Win64"

mysql-test/include/maria_empty_logs.inc:
  move mysqladmin call to include file for reusal (so that others don't have to hit the same bug in their tests);
  this include file additionally waits for disconnection. Reasons for BUG#41102:
  - in maria-no-logging.test, we shut down mysqld in maria_empty_logs.inc, remove logs, tell mtr that it can
  restart mysqld, then wait for being connected (wait_until_connected_again.inc), then send commands to new mysqld.
  - but under Windows "mysqladmin shutdown" does not wait for mysqld to be down, so we accidentally removed logs
  while it was shutting down, wait_until_connected_again found that we were connected (because it was shutting
  down slowly, connections were not yet broken), sent new commands, and one of them failed because mysqld finally
  closed connections.
  - the fix is to just wait for disconnection after shutdown.
  - in a sense, the catch is the "again" in wait_until_connected_again.inc...
mysql-test/include/mysqladmin_shutdown.inc:
  shutdown with mysqladmin AND waiting for shutdown to complete (needed on Windows)
mysql-test/include/wait_until_connected_again.inc:
  comment
mysql-test/include/wait_until_disconnected.inc:
  script which waits until connection is lost

mysql-test/include/maria_empty_logs.inc

@@ -13,7 +13,7 @@ append_file $MYSQLTEST_VARDIR/tmp/master0.expect;
 wait-maria_empty_logs.inc
 EOF
 
---exec $MYSQLADMIN --no-defaults -S $MASTER_MYSOCK -P $MASTER_MYPORT  -u root --password= shutdown 2>&1;
+--source include/mysqladmin_shutdown.inc
 
 if (!$mel_keep_control_file)
 {

mysql-test/include/mysqladmin_shutdown.inc

+# Initiates a clean shutdown of the server and waits for its completion
+
+--exec $MYSQLADMIN --no-defaults -S $MASTER_MYSOCK -P $MASTER_MYPORT  -u root --password= shutdown 2>&1;
+
+# On Windows mysqladmin does not wait for shutdown to be finished,
+# so we have to monitor this with our connection:
+--source include/wait_until_disconnected.inc

mysql-test/include/wait_until_connected_again.inc

@@ -2,6 +2,9 @@
 # Include this script to wait until the connection to the
 # server has been restored or timeout occurs.
 # You should have done --enable_reconnect first
+# When you change this file you may have to chance its cousin
+# wait_until_disconnected.inc
+
 --disable_result_log
 --disable_query_log
 let $counter= 5000;

mysql-test/include/wait_until_disconnected.inc

+#
+# Include this script after a shutdown to wait until the connection
+# to the server has been lost or timeout occurs.
+# When you change this file you may have to chance its cousin
+# wait_until_connected_again.inc
+
+--disable_result_log
+--disable_query_log
+let $counter= 5000;
+let $mysql_errno= 0;
+while (!$mysql_errno)
+{
+  --error 0,2002,2003,2006,1053
+  show status;
+
+  dec $counter;
+  if (!$counter)
+  {
+    --die Server failed to disconnect me
+  }
+  --sleep 0.1
+}
+--enable_query_log
+--enable_result_log