remote-mediawiki tests: use test_cmp in tests

Change code that used an ad-hoc "diff -b" invocation to use our
test_cmp helper instead. I'm also changing the order of arguments to
be the standard "test_cmp <expected> <actual>".

Using test_cmp has different semantics since the "-b" option to diff
causes it to ignore whitespace, but in these cases the use of "-b" was
just meaningless boilerplate. The desired semantics here are to
compare "git log" lines with know-good data, so we don't want to
ignore whitespace.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/mw-to-git/t/t9360-mw-to-git-clone.sh

@@ -28,7 +28,7 @@ test_expect_success 'Git clone creates the expected git log with one file' '
 		git log --format=%s HEAD^..HEAD >log.tmp
 	) &&
 	echo "this must be the same" >msg.tmp &&
-	diff -b mw_dir_1/log.tmp msg.tmp
+	test_cmp msg.tmp mw_dir_1/log.tmp
 '
 
 
@@ -50,8 +50,8 @@ test_expect_success 'Git clone creates the expected git log with multiple files'
 	echo "this must be the same" >>msgDaddy.tmp &&
 	echo "identical too" >msgDj.tmp &&
 	echo "identical" >>msgDj.tmp &&
-	diff -b mw_dir_2/logDaddy.tmp msgDaddy.tmp &&
-	diff -b mw_dir_2/logDj.tmp msgDj.tmp
+	test_cmp msgDaddy.tmp mw_dir_2/logDaddy.tmp &&
+	test_cmp msgDj.tmp mw_dir_2/logDj.tmp
 '
 
 
@@ -135,7 +135,7 @@ test_expect_success 'Git clone works with one specific page cloned ' '
 		cd mw_dir_8 &&
 		echo "this log must stay" >msg.tmp &&
 		git log --format=%s >log.tmp &&
-		diff -b msg.tmp log.tmp
+		test_cmp msg.tmp log.tmp
 	) &&
 	wiki_check_content mw_dir_8/Namnam.mw Namnam
 '