Rename LockReleaseMPM to LockRelease. This name was changed because of a clash with a symbol in ScriptWorks, and that's no longer a concern. See <https://info.ravenbrook.com/project/mps/import/2001-09-27/mminfo/doc/meeting/general/1997-02-19>. If we get symbol name clashes in future, we can try the .name.single strategy, or maybe objcopy --prefix.
Design for the multi-threaded testing module.