Add a (currently very permissive) test name check

We now get a framework failure if a test name doesn't match
^[a-zA-Z0-9][a-zA-Z0-9._/-]*$
Don't allow '/' characters in test names
MERGED: Use .hpc.<testname> for the hpc directory

All tests used to use .hpc, which caused failures when running in
parallel.
Clean the .hpc directories