MDEV-6247: Merge 10.0-galera to 10.1.

Merged lp:maria/maria-10.0-galera up to revision 3879.

Added a new functions to handler API to forcefully abort_transaction,
producing fake_trx_id, get_checkpoint and set_checkpoint for XA. These
were added for future possiblity to add more storage engines that
could use galera replication.

mysql-test/include/galera_init.inc

@@ -0,0 +1,26 @@
+# galera_init.inc
+# ===============
+#
+# Description
+# -----------
+# Set up a Galera cluster with $wsrep_cluster_size nodes.
+#
+# Parameters
+# ----------
+# $galera_cluster_size
+#   Number of nodes in the cluster.
+#
+
+--source include/have_wsrep_enabled.inc
+
+--let $_galera_node= $galera_cluster_size
+
+while ($_galera_node)
+{
+  --let $galera_connection_name= node_$_galera_node
+  --let $galera_server_number= $_galera_node
+  --source include/galera_connect.inc
+
+  --dec $_galera_node
+}
+