test-suite: Make test script numbers unique

In order to selectively skip tests, the environment variable GIT_SKIP_TESTS can be set like this: $ GIT_SKIP_TESTS='t1301 t4150.18' make test That is, its value can contain only the test script numbers, but not the full script name. Therefore, it is important that the test scripts are uniquely numbered. This makes it so. Signed-off-by: Johannes Sixt <j6t@kdbg.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>