Have you been able in the past to run both instances on the same machine?
Kill the test instance using OS commands. I don't think you'll be able to shut it down using Oracle commands such as SVRMGRL>SHUTDOWN ABORT, but you can try this first. Use OS commands to verify that all TEST processes are down.
BTW, I did all of the following for my own database and it worked for me.

1.) Move all control files for the test database to another location for temporary storage. Make sure no control files exist in the locations specified in the parameter file.
2.) edit the trace dump file, remove all the garbage at the top and remove the startup nomount command. The first operational command in the file should be the CREATE CONTROLFILE statement
3.) SVRMGRL>Startup nomount pfile=inittest.ora (or whatever the complete path and filename for your TEST initialization parameter file is.)
Does this work?
4.) svrmgrl>@recreate_control_file_script

This should do it for you.