[test] Allow self-tests to be run individually

Separate out the list of self-tests from the self-test infrastructure.
This allows tests to be run individually.  For example:

  make bin/sha1_test.iso

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/tests/test.c

 struct init_fn test_init_fn __init_fn ( INIT_NORMAL ) = {
 	.initialise = test_init,
 };
-
-/* Drag in all applicable self-tests */
-REQUIRE_OBJECT ( list_test );
-REQUIRE_OBJECT ( sha1_test );
-REQUIRE_OBJECT ( hmac_drbg_test );
-REQUIRE_OBJECT ( hash_df_test );

src/tests/tests.c

+/*
+ * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/** @file
+ *
+ * Self-test collection
+ *
+ */
+
+/* Drag in all applicable self-tests */
+REQUIRE_OBJECT ( list_test );
+REQUIRE_OBJECT ( sha1_test );
+REQUIRE_OBJECT ( hmac_drbg_test );
+REQUIRE_OBJECT ( hash_df_test );