Add a missing push_back

This is a horrible way to do things...
Don't try to CATD single-word nodes

The general idea here is that some nodes still need to be multi-word
expanded but are actually single word outputs (for example rsh/1
.../64).  These do not, however, need to be CATD'd into place because
they're already the correct name.
Fix a shift bounds error

This fixes one of the troubles with 0-width operands.
Allow for non-test named tests

This lets me just copy stuff in and symlink everything around.
Add a shift test

This is a small test for right-shifts.  This sort of pattern shows up
a whole lot in the DES code but unfortunately appears to work OK.