MDEV-37809 : MSAN use-of-uninitialized-value in wsrep_xid_print

Uninitialized value was created by an allocation of 'xid' in the
stack frame. Fixed by explicit initialization of xid.

Author: janlindstrom

sql/wsrep_xid.cc

@@ -42,6 +42,14 @@
 #define WSREP_XID_RPL_GTID_OFFSET (WSREP_XID_SEQNO_OFFSET + sizeof(wsrep_seqno_t))
 #define WSREP_XID_GTRID_LEN_V_3 (WSREP_XID_RPL_GTID_OFFSET + sizeof(wsrep_server_gtid_t))
 
+void inline wsrep_xid_init(XID *xid)
+{
+  xid->null();
+  xid->gtrid_length= 0;
+  xid->bqual_length= 0;
+  memset(xid->data, 0, sizeof(xid->data));
+}
+
 void wsrep_xid_init(XID* xid, const wsrep::gtid& wsgtid, const wsrep_server_gtid_t& gtid)
 {
   xid->formatID= 1;
@@ -161,8 +169,6 @@ bool wsrep_get_SE_checkpoint(XID& xid)
 
 static bool wsrep_get_SE_checkpoint_common(XID& xid)
 {
-  xid.null();
-
   if (wsrep_get_SE_checkpoint(xid))
   {
     return FALSE;
@@ -186,6 +192,7 @@ template<>
 wsrep::gtid wsrep_get_SE_checkpoint()
 {
   XID xid;
+  wsrep_xid_init(&xid);
 
   if (!wsrep_get_SE_checkpoint_common(xid))
   {
@@ -199,6 +206,7 @@ template<>
 wsrep_server_gtid_t wsrep_get_SE_checkpoint()
 {
   XID xid;
+  wsrep_xid_init(&xid);
   wsrep_server_gtid_t gtid= {0,0,0};
 
   if (!wsrep_get_SE_checkpoint_common(xid))