Use printf to handle test string containing escapes more portable

Works with both bash and dash. This reintroduces the fix to the
test-sgml-parser-basic test, and also fixes test-sgml-parser-incremental
and test-sgml-parser-lines, which Witek has reported as failing.

src/dom/test/test-sgml-parser-basic

@@ -20,7 +20,7 @@ test_output_equals () {
 
 	sgml-parser --uri "$URI" --src "$src" > output
 	echo "#document: $URI" > expected
-	echo "$out" | sed -n '2,$p' | sed 's/^/  /' >> expected
+	printf "%s\n" "$out" | sed -n '2,$p' | sed 's/^/  /' >> expected
 
 	test_expect_success "$desc" 'cmp output expected' 
 }

src/dom/test/test-sgml-parser-incremental

@@ -19,10 +19,10 @@ test_incremental_parsing () {
 	URI="test:$(normalize "$desc")"
 
 	echo "#document: $URI" > expected
-	echo "$out" | sed -n '2,$p' | sed -e 's/^/  /' >> expected
+	printf "%s\n" "$out" | sed -n '2,$p' | sed -e 's/^/  /' >> expected
 
 	for size in 1 2 3 4 5 6 7 8 9 10 15 20 25 50; do
-		echo -n "$src" | sgml-parser --uri "$URI" --stdin "$size" > output
+		printf "%s" "$src" | sgml-parser --uri "$URI" --stdin "$size" > output
 
 		test_run_ 'cmp output expected'
 		if [ "$?" != 0 -o "$eval_ret" != 0 ]

src/dom/test/test-sgml-parser-lines

@@ -55,10 +55,10 @@ test_output_line_numbers \
 7
 8' \
 8
- 
+
 test_output_line_numbers \
 'Check line numbers. (IIII)' \
-$'1\r\f 2\v\n 3\r\n 4\t\f 5' \
+"$(printf "1\r\f 2\v\n 3\r\n 4\t\f 5")" \
 5
-
+ 
 test_done