faccessat.test: robustify against libcs invoking faccessat syscall on their own

* tests/faccessat.c (TMP_FILE): Rename to sample, change its value
to "faccessat.sample".
* tests/faccessat.test: Rewrite using openat.test.

tests/faccessat.c

@@ -7,15 +7,15 @@
 # include <stdio.h>
 # include <unistd.h>
 
-# define TMP_FILE "faccessat_tmpfile"
-
 int
 main(void)
 {
+	static const char sample[] = "faccessat.sample";
 	const long int fd = (long int) 0xdeadbeefffffffff;
-	int rc = syscall(__NR_faccessat, fd, TMP_FILE, F_OK);
+
+	int rc = syscall(__NR_faccessat, fd, sample, F_OK);
 	printf("faccessat(%d, \"%s\", F_OK) = %d %s (%m)\n",
-	       (int) fd, TMP_FILE, rc,
+	       (int) fd, sample, rc,
 	       errno == ENOSYS ? "ENOSYS" : "EBADF");
 
 	puts("+++ exited with 0 +++");

tests/faccessat.test

@@ -2,10 +2,4 @@
 
 # Check faccessat syscall decoding.
 
-. "${srcdir=.}/init.sh"
-
-run_prog > /dev/null
-OUT="$LOG.out"
-run_strace -efaccessat $args > "$OUT"
-match_diff "$LOG" "$OUT"
-rm -f "$OUT"
+. "${srcdir=.}/openat.test"