update test_random to allow a different tbse script

src/perl/scripts2/test_random.pl

@@ -107,7 +107,8 @@ sub runsystem
     else
     {
         my $s = IO::Select->new();
-        my $cmd = "env VALGRIND_ARGS=\"--log-file=/dev/stdout\" stdbuf -i 0 -e 0 -o 0 $nice $timeout tbse $valgrind --repeat $repeat --random_systems 1 --log_filename /tmp/c_log-$n.dat  2>&1 ";
+        my $tbse = $ENV{'tbse'} // 'tbse';
+        my $cmd = "env VALGRIND_ARGS=\"--log-file=/dev/stdout\" stdbuf -i 0 -e 0 -o 0 $nice $timeout $tbse $valgrind --repeat $repeat --random_systems 1 --log_filename /tmp/c_log-$n.dat  2>&1 ";
         #print "CMD \n$cmd\n";
 
         my $args;