test-lib: output a newline before "ok" under a TAP harness

Some tests in the testsuite will emit a line that doesn't end with a
newline, right before we're about to output "ok" or "not ok". This
breaks the TAP output with "Tests out of sequence" errors since a TAP
harness can't understand this:

    ok 1 - A test
    [some output here]ok 2 - Another test
    ok 3 - Yet another test

Work around it by emitting an empty line before we're about to say
"ok" or "not ok", but only if we're running under --verbose and
HARNESS_ACTIVE=1 is set, which'll only be the case when running under
a harnesses like prove(1).

I think it's better to do this than fix each tests by adding `&& echo'
everywhere. More tests might be added that break TAP in the future,
and a human isn't going to look at the extra whitespace, since
HARNESS_ACTIVE=1 always means a harness is reading it.

The tests that had issues were:

   t1007, t3410, t3413, t3409, t3414, t3415, t3416, t3412, t3404,
   t5407, t7402, t7003, t9001

With this workaround the entire test suite runs without errors under:

    prove -j 10 ./t[0-9]*.sh :: --verbose
Signed-off-by: NÆvar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

t/test-lib.sh

@@ -371,6 +371,9 @@ test_run_ () {
 	eval >&3 2>&4 "$1"
 	eval_ret=$?
 	eval >&3 2>&4 "$test_cleanup"
+	if test "$verbose" = "t" && test -n "$HARNESS_ACTIVE"; then
+		echo ""
+	fi
 	return 0
 }