When add_test(NAME) is called without the CONFIGURATIONS argument then
the test is intended to run in any configuration.  In multi-config
generators like the VS IDE and Xcode tests created by add_test(NAME) can
only be run when testing a known configuration (otherwise there is no
way to generate the test command line).  If no test command line is
known for a particular configuration, or if no configuration is given to
ctest, report the test as not run instead of silently skipping it.

Also fix CMake's own TestsWorkingDirectory test invocation to correct a
previously silent failure exposed by this change.