Bug#42797 mtr.pl - temporary directory are deleted when child exit's

- Since we are only using the auto cleanup in one place of mtr.pl today, disable the
autocleanup and write our own END handler that clean up the tmpdir only when the process
that created it exits.

mysql-test/mysql-test-run.pl

@@ -107,6 +107,17 @@ our $default_vardir;
 our $opt_vardir;                # Path to use for var/ dir
 my $path_vardir_trace;          # unix formatted opt_vardir for trace files
 my $opt_tmpdir;                 # Path to use for tmp/ dir
+my $opt_tmpdir_pid;
+
+END {
+  if (defined $opt_tmpdir_pid and
+      $opt_tmpdir_pid == $$){
+    # Remove the tempdir this process has created
+    mtr_verbose("Removing tmpdir '$opt_tmpdir");
+    rmtree($opt_tmpdir);
+  }
+}
+
 my $path_config_file;           # The generated config file, var/my.cnf
 
 # Visual Studio produces executables in different sub-directories based on the
@@ -1066,8 +1077,11 @@ sub command_line_setup {
 		 " creating a shorter one...");
 
       # Create temporary directory in standard location for temporary files
-      $opt_tmpdir= tempdir( TMPDIR => 1, CLEANUP => 1 );
+      $opt_tmpdir= tempdir( TMPDIR => 1, CLEANUP => 0 );
       mtr_report(" - using tmpdir: '$opt_tmpdir'\n");
+
+      # Remember pid that created dir so it's removed by correct process
+      $opt_tmpdir_pid= $$;
     }
   }
   $opt_tmpdir =~ s,/+$,,;       # Remove ending slash if any