Fix output of Unicode normalization test

Several off-by-more-than-one errors caused the output in case of a
test failure to be truncated and unintelligible.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/6a7a8516-7d11-8fbd-0e8b-eadb4f0679eb%402ndquadrant.com

src/common/unicode/norm_test.c

@@ -23,17 +23,20 @@ static char *
 print_wchar_str(const pg_wchar *s)
 {
 #define BUF_DIGITS 50
-	static char buf[BUF_DIGITS * 2 + 1];
+	static char buf[BUF_DIGITS * 11 + 1];
 	int			i;
+	char	   *p;
 
 	i = 0;
+	p = buf;
 	while (*s && i < BUF_DIGITS)
 	{
-		snprintf(&buf[i * 2], 3, "%04X", *s);
+		p += sprintf(p, "U+%04X ", *s);
 		i++;
 		s++;
 	}
-	buf[i * 2] = '\0';
+	*p = '\0';
+
 	return buf;
 }
 
@@ -67,9 +70,9 @@ main(int argc, char **argv)
 		if (pg_wcscmp(test->output, result) != 0)
 		{
 			printf("FAILURE (NormalizationTest.txt line %d):\n", test->linenum);
-			printf("input:\t%s\n", print_wchar_str(test->input));
-			printf("expected:\t%s\n", print_wchar_str(test->output));
-			printf("got\t%s\n", print_wchar_str(result));
+			printf("input:    %s\n", print_wchar_str(test->input));
+			printf("expected: %s\n", print_wchar_str(test->output));
+			printf("got:      %s\n", print_wchar_str(result));
 			printf("\n");
 			exit(1);
 		}