Create a CTEST_TEST_DEVENV variable that is set to the
CMAKE_MAKE_PROGRAM used for Visual Studio 7, 8, and 9.  It will always
be either "devenv" or "VCExpress", and not "MSBuild".  Add the
VSExcludeFromDefaultBuild test only when this variable is set, and use
its value as the --build-makeprogram value.

More work will be needed later to restore the test on VS 10 and above
when devenv is available, but this is the simplest approach for now.