t4214: use test_merge

In the previous commit, we extended test_merge() so that it could
perform octopus merges. Now that the restriction is lifted, use
test_merge() to perform the octopus merge instead of manually
duplicating test_merge() functionality.

Signed-off-by: Denton Liu <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: Denton-L

t/t4214-log-graph-octopus.sh

@@ -41,8 +41,7 @@ test_expect_success 'set up merge history' '
 		test_commit $i $i $i tag$i || return $?
 	done &&
 	git checkout 1 -b merge &&
-	test_tick &&
-	git merge -m octopus-merge 1 2 3 4 &&
+	test_merge octopus-merge 1 2 3 4 &&
 	git checkout 1 -b L &&
 	test_commit left
 '