This is a pair of test modules I'd like to see in the tree.  Instead of
putting these in lkdtm, where I've been adding various tests that trigger
crashes, these don't make sense there since they need to be either
distinctly separate, or their pass/fail state don't need to crash the
machine.

These live in lib/ for now, along with a few other in-kernel test modules,
and use the slightly more common "test_" naming convention, instead of
"test-".  We should likely standardize on the former:

$ find . -name 'test_*.c' | grep -v /tools/ | wc -l
4
$ find . -name 'test-*.c' | grep -v /tools/ | wc -l
2

The first is entirely a no-op module, designed to allow simple testing of
the module loading and verification interface.  It's useful to have a
module that has no other uses or dependencies so it can be reliably used
for just testing module loading and verification.

The second is a module that exercises the user memory access functions, in
an effort to make sure t...