Fix tests under GETTEXT_POISON on diffstat

Use the i18n-specific test functions in test scripts for diffstat.
This issue was was introduced in v1.7.9-1-g7f814:

    7f814 Use correct grammar in diffstat summary line

and been broken under GETTEXT_POISON=YesPlease since.

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t4006-diff-mode.sh

@@ -36,24 +36,24 @@ test_expect_success '--stat output after text chmod' '
 	test_chmod -x rezrov &&
 	echo " 0 files changed" >expect &&
 	git diff HEAD --stat >actual &&
-	test_cmp expect actual
+	test_i18ncmp expect actual
 '
 
 test_expect_success '--shortstat output after text chmod' '
 	git diff HEAD --shortstat >actual &&
-	test_cmp expect actual
+	test_i18ncmp expect actual
 '
 
 test_expect_success '--stat output after binary chmod' '
 	test_chmod +x binbin &&
 	echo " 0 files changed" >expect &&
 	git diff HEAD --stat >actual &&
-	test_cmp expect actual
+	test_i18ncmp expect actual
 '
 
 test_expect_success '--shortstat output after binary chmod' '
 	git diff HEAD --shortstat >actual &&
-	test_cmp expect actual
+	test_i18ncmp expect actual
 '
 
 test_done

t/t4202-log.sh

@@ -803,7 +803,7 @@ sanitize_output () {
 test_expect_success 'log --graph with diff and stats' '
 	git log --graph --pretty=short --stat -p >actual &&
 	sanitize_output >actual.sanitized <actual &&
-	test_cmp expect actual.sanitized
+	test_i18ncmp expect actual.sanitized
 '
 
 test_done

t/t4205-log-pretty-formats.sh

@@ -88,15 +88,15 @@ test_expect_success 'NUL separation with --stat' '
 	stat1_part=$(git diff --stat --root HEAD^) &&
 	printf "add bar\n$stat0_part\n\0initial\n$stat1_part\n" >expected &&
 	git log -z --stat --pretty="format:%s" >actual &&
-	test_cmp expected actual
+	test_i18ncmp expected actual
 '
 
 test_expect_failure 'NUL termination with --stat' '
 	stat0_part=$(git diff --stat HEAD^ HEAD) &&
 	stat1_part=$(git diff --stat --root HEAD^) &&
 	printf "add bar\n$stat0_part\n\0initial\n$stat1_part\n\0" >expected &&
 	git log -z --stat --pretty="tformat:%s" >actual &&
-	test_cmp expected actual
+	test_i18ncmp expected actual
 '
 
 test_done

t/t7508-status.sh

@@ -80,7 +80,7 @@ test_expect_success 'status --column' '
 #	dir1/untracked dir2/untracked untracked
 #	dir2/modified  output
 EOF
-	test_cmp expect output
+	test_i18ncmp expect output
 '
 
 cat >expect <<\EOF