Fix argument parsing in test(1) and chmod(1)

We just take the raw argument list as is. Using arg.h, arguments
beginning with - would have been "eaten up".
Writing a special "bailout" for arg.h was not a good option,
not because it's not impossible (done in 6 LOC), but because it
is a shoehorning around a corner case present for a few programs
which are broken by design by POSIX.

test.c

@@ -148,10 +148,7 @@ main(int argc, char *argv[])
 	int (*narg[])(char *[]) = { noarg, onearg, twoarg, threearg, fourarg };
 	size_t len;
 
-	ARGBEGIN {
-	default:
-		break;
-	} ARGEND;
+	argv0 = argv[0], argc--, argv++;
 
 	len = strlen(argv0);
 	if (len && argv0[--len] == '[' && (!len || argv0[--len] == '/') && strcmp(argv[--argc], "]"))