MDEV-16944 Fix file sharing issues on Windows in mysqltest

On Windows systems, occurrences of ERROR_SHARING_VIOLATION due to
conflicting share modes between processes accessing the same file can
result in CreateFile failures.

mysys' my_open() already incorporates a workaround by implementing
wait/retry logic on Windows.

But this does not help if files are opened using shell redirection like
mysqltest traditionally did it, i.e via

--echo exec "some text" > output_file

In such cases, it is cmd.exe, that opens the output_file, and it
won't do any sharing-violation retries.

This commit addresses the issue by introducing a new built-in command,
'write_line', in mysqltest. This new command serves as a brief alternative
to 'write_file', with a single line output, that also resolves variables
like "exec" would.

Internally, this command will use my_open(), and therefore retry-on-error
logic.

Hopefully this will eliminate the very sporadic "can't open file because
it is used by another process" error on CI.

mysql-test/suite/perfschema/t/bad_option.test

@@ -13,7 +13,7 @@ let $error_log= $MYSQLTEST_VARDIR/log/my_restart.err;
 let SEARCH_FILE= $error_log;
 # Stop the server
 let $restart_file= $MYSQLTEST_VARDIR/tmp/mysqld.1.expect;
---exec echo "wait" > $restart_file
+--write_line wait $restart_file
 --shutdown_server 
 --source include/wait_until_disconnected.inc
 --error 7
@@ -61,7 +61,7 @@ let SEARCH_PATTERN= Can.t change dir to .*bad_option_h_param;
 
 --remove_file $error_log
 # Write file to make mysql-test-run.pl start up the server again
---exec echo "restart" > $restart_file
+--write_line restart $restart_file
 
 # Turn on reconnect
 --enable_reconnect

mysql-test/suite/perfschema/t/processlist_57.test

@@ -23,7 +23,7 @@ DROP TABLE performance_schema.processlist;
 SHOW CREATE TABLE performance_schema.processlist;
 
 let $restart_file= $MYSQLTEST_VARDIR/tmp/mysqld.1.expect;
---exec echo "wait" > $restart_file
+--write_line wait $restart_file
 --echo ##
 --echo ## Server shutdown
 --echo ##
@@ -93,7 +93,7 @@ SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
 --error ER_BAD_FIELD_ERROR
 SHOW PROCESSLIST;
 
---exec echo "wait" > $restart_file
+--write_line wait $restart_file
 --echo ##
 --echo ## Server shutdown
 --echo ##
@@ -166,7 +166,7 @@ SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
 # Works and returns no data, innodb table is empty.
 SHOW PROCESSLIST;
 
---exec echo "wait" > $restart_file
+--write_line wait $restart_file
 --echo ##
 --echo ## Server shutdown
 --echo ##
@@ -231,7 +231,7 @@ SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
 # Works and returns no data, innodb table is empty.
 SHOW PROCESSLIST;
 
---exec echo "wait" > $restart_file
+--write_line wait $restart_file
 --echo ##
 --echo ## Server shutdown
 --echo ##
@@ -306,7 +306,7 @@ SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
 --replace_column 3 [HOST:PORT] 6 [TIME]
 SHOW PROCESSLIST;
 
---exec echo "wait" > $restart_file
+--write_line wait $restart_file
 --echo ##
 --echo ## Server shutdown
 --echo ##

mysql-test/suite/perfschema/t/setup_instruments_defaults.test

@@ -69,7 +69,7 @@ SELECT * FROM performance_schema.setup_instruments
 WHERE name like "%wait/io/table/sql/handler%";
 
 # Write file to make mysql-test-run.pl wait for the server to stop
---exec echo "wait" > $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
+--write_line wait $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
 
 # Restart the server
 --echo #
@@ -79,7 +79,7 @@ WHERE name like "%wait/io/table/sql/handler%";
 
 --echo # Restart server with wait/io/table/sql/handler disabled
 
---exec echo "restart:--loose-performance-schema-instrument=%wait/io/table/sql/%=off" > $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
+--write_line "restart:--loose-performance-schema-instrument=%wait/io/table/sql/%=off"  $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
 
 # Turn on reconnect
 --echo # Enable reconnect

mysql-test/suite/perfschema/t/statement_program_lost_inst.test

@@ -19,10 +19,10 @@
 --source include/have_perfschema.inc
 
 let $restart_file= $MYSQLTEST_VARDIR/tmp/mysqld.1.expect;
---exec echo "wait" > $restart_file
+--write_line wait $restart_file
 --shutdown_server 
 --source include/wait_until_disconnected.inc
---exec echo "restart:--performance_schema_max_program_instances=7 --performance_schema_max_statement_stack=2 --thread_stack=655360">$restart_file
+--write_line "restart:--performance_schema_max_program_instances=7 --performance_schema_max_statement_stack=2 --thread_stack=655360" $restart_file
 --enable_reconnect
 --source include/wait_until_connected_again.inc