tests: convert several tests from match_grep to match_diff

* tests/sendfile.test: Use match_diff instead of match_grep.
* tests/sendfile64.test: Likewise.
* tests/time.test: Likewise.
* tests/utime.test: Likewise.
* tests/xet_robust_list.test: Likewise.
* tests/sendfile.c (main): Update match patterns for match_diff.
* tests/sendfile64.c (main): Likewise.
* tests/time.c (main): Likewise.
* tests/utime.c (main): Likewise.
* tests/xet_robust_list.c (main): Likewise.
diff --git a/tests/utime.c b/tests/utime.c
index 0298b27..c1af785 100644
--- a/tests/utime.c
+++ b/tests/utime.c
@@ -18,11 +18,12 @@
 	struct utimbuf u = { .actime = t, .modtime = t };
 	struct tm *p = localtime(&t);
 
-	printf("utime\\(\"utime\\\\nfilename\", \\[");
+	printf("utime(\"utime\\nfilename\", [");
 	print_tm(p);
 	printf(", ");
 	print_tm(p);
-	printf("\\]\\) += -1 ENOENT .*\n");
+	puts("]) = -1 ENOENT (No such file or directory)");
+	puts("+++ exited with 0 +++");
 
 	return utime("utime\nfilename", &u) == -1 && errno == ENOENT ? 0 : 77;
 }