t6050: use test_line_count instead of wc -l

This modernizes a test and makes it more portable.

Reviewed-by: Taylor Blau <[email protected]>
Signed-off-by: Christian Couder <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: chriscool

t/t6050-replace.sh

@@ -393,9 +393,11 @@ test_expect_success 'replace ref cleanup' '
 '
 
 test_expect_success '--graft with and without already replaced object' '
-	test $(git log --oneline | wc -l) = 7 &&
+	git log --oneline >log &&
+	test_line_count = 7 log &&
 	git replace --graft $HASH5 &&
-	test $(git log --oneline | wc -l) = 3 &&
+	git log --oneline >log &&
+	test_line_count = 3 log &&
 	commit_has_parents $HASH5 &&
 	test_must_fail git replace --graft $HASH5 $HASH4 $HASH3 &&
 	git replace --force -g $HASH5 $HASH4 $HASH3 &&