log tests: fix "abort tests early" regression in ff37a60

Fix a regression in ff37a60 (log tests: check if grep_config() is
called by "log"-like cmds, 2022-02-16), a "test_done" command used
during development made it into a submitted patch causing tests 41-136
in t/t4202-log.sh to be skipped.

Reported-by: Fabian Stelzer <[email protected]>
Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

t/t4202-log.sh

@@ -471,7 +471,6 @@ do
 		)
 	'
 done
-test_done
 
 test_expect_success 'log --author' '
 	cat >expect <<-\EOF &&