TESTS: Make check_leaks static function Reviewed-by: Petr Cech <pcech@redhat.com>

TESTS: Check return value of check_leaks_pop Reviewed-by: Petr Cech <pcech@redhat.com>

test: avoid leaks in leak tests Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>

TESTS: leak_check functions shouldn't be called with NULL context Memory leaks will not be detected if talloc context is NULL. Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>

Making order in tests. --removed duplicated test-io --reusing library libsss_test_common in other tests --cmocka test sss_nss_idmap-tests was moved to cmocka dir --moved leak_check.c to libsss_test_common --moved common_tev.c,common_dom.c to libsss_test_common (leak_check.c,common_tev.c,common_dom.c) are test framework independent

Make leak checks usable in tests that do not utilize check * Remove check-specific failure reporting from common_check.c * Check-specific abstraction over memleak checks * Rename common_check.c to leak_check.c