Prevent adding WSREP keys with CTAS when table is is not InnoDB.

Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>

* reuse the loop in THD::abort_current_cond_wait, don't duplicate it
* find_thread_by_id should return whatever it has found, it's the
  caller's task not to kill COM_DAEMON (if the caller's a killer)

and other minor changes

Problem: Assertion `transactional_table || !changed ||
thd->transaction.stmt.modified_non_trans_table' failed due REPLACE into a
versioned table.

It is not specific to system versioning/pertitioning/heap, but this
combination makes it much easier to reproduce.

The thing is to make first ha_update_row call succeed to make
info->deleted != 0. And then make REPLACE fail by any reason.

In this scenario we overflow versioned partition, so next ha_update_row
succeeds, but corresponding ha_write_row fails to insert history record.

Fix: modified_non_trans_table is set in one missed place

ip_len has a different meaning on AIX so we use a
different variable name here not to conflict.

Backport from MDEV-20178 2f5d372444cff53914cfcd118e92a91f575cec35

The Galera tests were massively failing with debug assertions.

The reason for the failure is that
thd->mdl_context.release_transactional_locks()
was called after commit & rollback even in cases where the current
transaction is still active.

For 10.2, 10.3 and 10.4 the fix is simple:
- Replace all calls to thd->mdl_context.release_transactional_locks() with
  thd->release_transactional_locks(). The thd function will only call
  the mdl_context function if there are no active transactional locks.
  In 10.6 we will better fix where we will change the return value for
  some trans_xxx() functions to indicate if transaction did close the
  transaction or not. This will avoid the need of the indirect call.

Other things:
- trans_xa_commit() and trans_xa_rollback() will automatically
  call release_transactional_locks() if the transaction is closed.
- We can't do that for the other functions as the caller of many of these
  are doing additional work (like close_thread_tables) before calling
  release_transactional_locks().
- Added missing abort_result_set() and missing DBUG_RETURN in
  select_create::send_eof()
- Fixed wrong indentation in injector::transaction::commit()