The verifier tests come from Mauve.
See http://sources.redhat.com/mauve

You want the "verify" module in the Mauve cvs repository.

In Mauve, only the sources are checked in.  However, these need
jasmin to be compiled to bytecode.  Since jasmin would require either
another VM or gcj itself to already be working and installed (just to
compile it), we've chose to precompile all the .j files to .class
files and then import the result.