CREATE TABLE with FOREIGN KEY constraint fails to apply in parallel

This issue was observed when testing the fix for MDEV-26803. There, in the test galera.galera_fk_cascade_delete, scenario 2, if the applier thread count in node 2 is raised to 2, before the test tables are created, it often happens that the table 'c' create applies in parallel with one of the 'p1' table inserts , and this fails with assertion.
Reason for this appears to be that create table with FK constraints does not append the referenced table names as keys in the write set.