[PATCH 1/2] Test suite fixup.

[PATCH 1/2] Test suite fixup.

Exposing test_expect_success and test_expect_failure turns out
to be enough for the test scripts and there is no need for
exposing test_ok or test_failure.  This patch cleans it up and
fixes the users of test_ok and test_failure.

Also test scripts have acquired a new command line flag
'--immediate' to cause them to exit upon the first failure.
This is useful especially during the development of a new test.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Petr Baudis <pasky@ucw.cz>