sched/posix_spawn: Don't insert name at the begin of argv

since the standard require the caller pass the name explicitly
https://pubs.opengroup.org/onlinepubs/009695399/functions/posix_spawn.html:
The argument argv is an array of character pointers to null-terminated strings.
The last member of this array shall be a null pointer and is not counted in argc.
These strings constitute the argument list available to the new process image.
The value in argv[0] should point to a filename that is associated with the
process image being started by the posix_spawn() or posix_spawnp() function.

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

sched/task/task_vfork.c

@@ -97,7 +97,6 @@ FAR struct task_tcb_s *nxtask_setup_vfork(start_t retaddr)
   FAR struct task_tcb_s *parent;
   FAR struct task_tcb_s *child;
   FAR struct task_info_s *info;
-  FAR const char *name = NULL;
   size_t stack_size;
   uint8_t ttype;
   int priority;
@@ -204,11 +203,7 @@ FAR struct task_tcb_s *nxtask_setup_vfork(start_t retaddr)
 
   /* Setup to pass parameters to the new task */
 
-#if CONFIG_TASK_NAME_SIZE > 0
-  name = parent->cmn.name;
-#endif
-
-  nxtask_setup_arguments(child, name, parent->argv);
+  nxtask_setup_arguments(child, parent->argv[0], &parent->argv[1]);
 
   /* Now we have enough in place that we can join the group */