use log-error in mtr, don't let mysqld to write to stderr

because on Windows it cannot properly append to the file,
doesn't use CreateFile(..., FILE_APPEND_DATA, ...)

this fixes main.shutdown failures on Windows

mysql-test/lib/My/ConfigFactory.pm

@@ -246,7 +246,7 @@ my @mysqld_rules=
  { '#host' => \&fix_host },
  { 'port' => \&fix_port },
  { 'socket' => \&fix_socket },
- { '#log-error' => \&fix_log_error },
+ { 'log-error' => \&fix_log_error },
  { 'general-log' => 1 },
  { 'plugin-dir' => sub { $::plugindir } },
  { 'general-log-file' => \&fix_log },
@@ -394,7 +394,7 @@ sub post_check_embedded_group {
 
   my %no_copy = map { $_ => 1 }
     (
-     '#log-error', # Embedded server writes stderr to mysqltest's log file
+     'log-error', # Embedded server writes stderr to mysqltest's log file
      'slave-net-timeout', # Embedded server are not build with replication
      'shared-memory-base-name', # No shared memory for embedded
     );

mysql-test/mysql-test-run.pl

@@ -2757,7 +2757,7 @@ ($)
     # Already started
 
     # Write start of testcase to log file
-    mark_log($mysqld->value('#log-error'), $tinfo);
+    mark_log($mysqld->value('log-error'), $tinfo);
 
     return;
   }
@@ -2814,7 +2814,7 @@ ($)
   mkpath($tmpdir) unless -d $tmpdir;
 
   # Write start of testcase to log file
-  mark_log($mysqld->value('#log-error'), $tinfo);
+  mark_log($mysqld->value('log-error'), $tinfo);
 
   # Run <tname>-master.sh
   if ($mysqld->option('#!run-master-sh') and
@@ -4259,7 +4259,7 @@ ($$)
 
   foreach my $mysqld (all_servers()) {
     if ($mysqld->{proc} eq $proc) {
-      my @srv_lines= extract_server_log($mysqld->if_exist('#log-error'), $name);
+      my @srv_lines= extract_server_log($mysqld->if_exist('log-error'), $name);
       $srv_log= "\nServer log from this test:\n" .
 	"----------SERVER LOG START-----------\n". join ("", @srv_lines) .
 	"----------SERVER LOG END-------------\n";
@@ -4466,7 +4466,7 @@ ($$)
 
   my $name= "warnings-".$mysqld->name();
 
-  my $log_error= $mysqld->value('#log-error');
+  my $log_error= $mysqld->value('log-error');
   # To be communicated to the test
   $ENV{MTR_LOG_ERROR}= $log_error;
   extract_warning_lines($log_error, 0);
@@ -4624,7 +4624,7 @@ sub check_warnings_post_shutdown {
   foreach my $mysqld ( mysqlds())
   {
     my ($testlist, $match_lines)=
-        extract_warning_lines($mysqld->value('#log-error'), 1);
+        extract_warning_lines($mysqld->value('log-error'), 1);
     $testname_hash->{$_}= 1 for @$testlist;
     $report.= join('', @$match_lines);
   }
@@ -5073,7 +5073,7 @@ ($$)
   # Remove the old pidfile if any
   unlink($mysqld->value('pid-file'));
 
-  my $output= $mysqld->value('#log-error');
+  my $output= $mysqld->value('log-error');
 
   if ( $opt_valgrind and $opt_debug )
   {

mysql-test/suite/sys_vars/r/log_error_func.result

@@ -1,6 +1,6 @@
 select (@err_log:=variable_value)*0 from information_schema.global_variables where variable_name="log_error";
 (@err_log:=variable_value)*0
 0
-select instr(@err_log, "some_random_name5435413.err")>0;
-instr(@err_log, "some_random_name5435413.err")>0
+select instr(@err_log, "mysqld.1.err")>0;
+instr(@err_log, "mysqld.1.err")>0
 1

mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result

@@ -1817,8 +1817,8 @@ READ_ONLY	NO
 COMMAND_LINE_ARGUMENT	OPTIONAL
 VARIABLE_NAME	LOG_ERROR
 SESSION_VALUE	NULL
-GLOBAL_VALUE	
-GLOBAL_VALUE_ORIGIN	COMPILE-TIME
+GLOBAL_VALUE	PATH
+GLOBAL_VALUE_ORIGIN	CONFIG
 DEFAULT_VALUE	0
 VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	VARCHAR

mysql-test/suite/sys_vars/t/log_error_func.test

@@ -1,10 +1,13 @@
+# embedded .cnf doesn't have log-error option
+source include/not_embedded.inc;
+
 # Test for BUG#51215 "log-error partially works with version 5.5"
 # when --log-error is used without argument
 
 # check displayed value. We can check only the base name, the rest
 # depends on paths, symbolic links, --vardir, etc...
 select (@err_log:=variable_value)*0 from information_schema.global_variables where variable_name="log_error";
-select instr(@err_log, "some_random_name5435413.err")>0;
+select instr(@err_log, "mysqld.1.err")>0;
 
 # Check file's existence. The displayed value may be relative or not.
 let $err_log=`select @err_log`;

mysql-test/suite/sys_vars/t/log_error_func2.opt

@@ -0,0 +1 @@
+--log-error

mysql-test/suite/sys_vars/t/log_error_func3.opt

@@ -0,0 +1 @@
+--disable-log-error

mysql-test/t/plugin_loaderr.test

@@ -18,7 +18,7 @@ FROM INFORMATION_SCHEMA.PLUGINS WHERE plugin_name = 'innodb';
 --source include/wait_until_disconnected.inc
 
 --error 1
---exec $MYSQLD_CMD --innodb=force --innodb-page-size=6000
+--exec $MYSQLD_CMD --innodb=force --innodb-page-size=6000 --disable-log-error
 
 --exec echo "restart" > $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
 --enable_reconnect