test: compare raw output, not mangle tabs and spaces

Before comparing with the expect file, we used to call function
"make_user_friendly_and_stable_output" to filter out trailing spaces in
output.  Ævar recommends using pattern "s/Z$//" to prepare expect file,
and then compare it with raw output.

Since we have fixed the issue of occasionally missing the clear-to-eol
suffix when displaying sideband #2 messages, it is safe and stable to
test against raw output.

Suggested-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t5411/common-functions.sh

@@ -33,17 +33,14 @@ create_commits_in () {
 
 # Format the output of git-push, git-show-ref and other commands to make a
 # user-friendly and stable text.  We can easily prepare the expect text
-# without having to worry about future changes of the commit ID and spaces
+# without having to worry about changes of the commit ID (full or abbrev.)
 # of the output.  Single quotes are replaced with double quotes, because
 # it is boring to prepare unquoted single quotes in expect text.  We also
 # remove some locale error messages. The emitted human-readable errors are
 # redundant to the more machine-readable output the tests already assert.
 make_user_friendly_and_stable_output () {
 	sed \
-		-e "s/  *\$//" \
-		-e "s/  */ /g" \
 		-e "s/'/\"/g" \
-		-e "s/	/    /g" \
 		-e "s/$A/<COMMIT-A>/g" \
 		-e "s/$B/<COMMIT-B>/g" \
 		-e "s/$TAG/<TAG-v123>/g" \
@@ -59,6 +56,10 @@ filter_out_user_friendly_and_stable_output () {
 		sed -n ${1+"$@"}
 }
 
+format_and_save_expect () {
+	sed -e 's/^> //' -e 's/Z$//' >expect
+}
+
 test_cmp_refs () {
 	indir=
 	if test "$1" = "-C"