[examples]Fixed an issue where fclose was not used after using fopen

examples/utest/testcases/posix/stdio_h/functions/perror_tc.c

@@ -8,7 +8,9 @@ static int perror_entry(void)
     {
         printf("perror test:");
         perror("nulltest.txt");
+        return -1;
     }
+    fclose(stream);
     return 0;
 }