Bug#58621 perfschema.dml_ews_by_thread_by_event_name test failure

This fix affects the test suite only.

Before this fix, performance schema tests dml_*.test could
fail with spurious failure, depending on the table content.

This fix simplifies the SELECT tests in the dml_*.test scripts,
to only verify that the SELECT operation passed the security checks
and succeeded, which was the original intent of the test.

Usage of 
  --replace_column 1 # 2 # 3 # 4 # ...
to discard the test output was replaced by a simpler and more maintainable 
  --disable_result_log
which also work for empty tables.

mysql-test/suite/perfschema/r/dml_threads.result

@@ -1,10 +1,7 @@
 select * from performance_schema.threads
 where name like 'Thread/%' limit 1;
-THREAD_ID	PROCESSLIST_ID	NAME
-#	#	#
 select * from performance_schema.threads
 where name='FOO';
-THREAD_ID	PROCESSLIST_ID	NAME
 insert into performance_schema.threads
 set name='FOO', thread_id=1, processlist_id=2;
 ERROR 42000: INSERT command denied to user 'root'@'localhost' for table 'threads'