Resolving the issue with the ltp_interfaces_pthread_join_6_2 test case.
In SMP mode, the pthread may still be in the process of exiting when
pthread_join returns, and calling pthread_join again at this time will
result in an error. The error code returned should be ESRCH.
Signed-off-by: zhangyuan21 <zhangyuan21@xiaomi.com>