test(junit): avoid line feeds in XML attributes

In the test case's output, we do want newline characters, but in the XML
attributes we do not want them.

However, the `xml_attr_encode` function always adds a Line Feed at the
end (which are then encoded as `
`, even for XML attributes.

This seems not to faze Azure Pipelines' XML parser, but it still is
incorrect, so let's fix it.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/test-lib-junit.sh

@@ -50,7 +50,7 @@ finalize_test_case_output () {
 		;;
 	failure)
 		junit_insert="<failure message=\"not ok $test_count -"
-		junit_insert="$junit_insert $(xml_attr_encode "$1")\">"
+		junit_insert="$junit_insert $(xml_attr_encode --no-lf "$1")\">"
 		junit_insert="$junit_insert $(xml_attr_encode \
 			"$(if test -n "$GIT_TEST_TEE_OUTPUT_FILE"
 			   then
@@ -74,12 +74,12 @@ finalize_test_case_output () {
 		set "$* (known breakage)"
 		;;
 	skip)
-		message="$(xml_attr_encode "$skipped_reason")"
+		message="$(xml_attr_encode --no-lf "$skipped_reason")"
 		set "$1" "      <skipped message=\"$message\" />"
 		;;
 	esac
 
-	junit_attrs="name=\"$(xml_attr_encode "$this_test.$test_count $1")\""
+	junit_attrs="name=\"$(xml_attr_encode --no-lf "$this_test.$test_count $1")\""
 	shift
 	junit_attrs="$junit_attrs classname=\"$this_test\""
 	junit_attrs="$junit_attrs time=\"$(test-tool \
@@ -122,5 +122,11 @@ write_junit_xml () {
 }
 
 xml_attr_encode () {
-	printf '%s\n' "$@" | test-tool xml-encode
+	if test "x$1" = "x--no-lf"
+	then
+		shift
+		printf '%s' "$*" | test-tool xml-encode
+	else
+		printf '%s\n' "$@" | test-tool xml-encode
+	fi
 }