porting里新增接口sched_setscheduler，修改musl_src.gni，新增对应测试用例并修改test_src_functional.gni

Signed-off-by: caifuzhou <504631861@qq.com>

porting/linux/user/src/sched/sched_setscheduler.c

@@ -11,7 +11,7 @@ int sched_setscheduler(pid_t pid, int sched, const struct sched_param *param)
 		goto exit;
 	}
 
-	r = __syscall(SYS_sched_setscheduler, pid, sched, param);//, MUSL_TYPE_PROCESS
+	r = __syscall(SYS_sched_setscheduler, pid , sched , param->sched_priority);
 ;
 exit: