Fix the TEST variable when CONFIG_TESTS is not set:
This is another bug exposed by the new menu system. The TEST variable was set
inside the menu "test settings". But this menu depends on CONFIG_TESTS, and
is not executed if CONFIG_TESTS is not set. So that, the TEST variable was
not set if CONFIG_TESTS was not set (while with the former menu suystem,
it was set to 0). Due to the logic in lfs.xsl, this resulted in all the
tests being run, instead of none...
Move the setting of the TEST variable outside the "test settings" menu.
