tests: remove most uses of test_i18ncmp

As a follow-up to d162b25f956 (tests: remove support for
GIT_TEST_GETTEXT_POISON, 2021-01-20) remove most uses of test_i18ncmp
via a simple s/test_i18ncmp/test_cmp/g search-replacement.

I'm leaving t6300-for-each-ref.sh out due to a conflict with in-flight
changes between "master" and "seen", as well as the prerequisite
itself due to other changes between "master" and "next/seen" which add
new test_i18ncmp uses.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/t1507-rev-parse-upstream.sh b/t/t1507-rev-parse-upstream.sh
index 73b4f34..c34714f 100755
--- a/t/t1507-rev-parse-upstream.sh
+++ b/t/t1507-rev-parse-upstream.sh
@@ -172,7 +172,7 @@
 	fatal: no upstream configured for branch ${SQ}non-tracking${SQ}
 	EOF
 	error_message non-tracking@{u} &&
-	test_i18ncmp expect error
+	test_cmp expect error
 '
 
 test_expect_success '@{u} error message when no upstream' '
@@ -180,7 +180,7 @@
 	fatal: no upstream configured for branch ${SQ}main${SQ}
 	EOF
 	test_must_fail git rev-parse --verify @{u} 2>actual &&
-	test_i18ncmp expect actual
+	test_cmp expect actual
 '
 
 test_expect_success 'branch@{u} error message with misspelt branch' '
@@ -188,7 +188,7 @@
 	fatal: no such branch: ${SQ}no-such-branch${SQ}
 	EOF
 	error_message no-such-branch@{u} &&
-	test_i18ncmp expect error
+	test_cmp expect error
 '
 
 test_expect_success '@{u} error message when not on a branch' '
@@ -197,7 +197,7 @@
 	EOF
 	git checkout HEAD^0 &&
 	test_must_fail git rev-parse --verify @{u} 2>actual &&
-	test_i18ncmp expect actual
+	test_cmp expect actual
 '
 
 test_expect_success 'branch@{u} error message if upstream branch not fetched' '
@@ -205,7 +205,7 @@
 	fatal: upstream branch ${SQ}refs/heads/side${SQ} not stored as a remote-tracking branch
 	EOF
 	error_message bad-upstream@{u} &&
-	test_i18ncmp expect error
+	test_cmp expect error
 '
 
 test_expect_success 'pull works when tracking a local branch' '