Changes

tests: do not copy *.cfg files to the build directory

When running 'make check' in-tree ($builddir == $srcdir), those
*.cfg files end up in tests/ and show up as git-add candidates.
Instead of copying them, just let the test binaries know where
to find those files via the cmdline parameters.

Change-Id: I74e428f0548418fdecada3d25049d6e110e790fe