reason:Add the following test cases to cover more interfaces of npth:
t-condlock.c test npth condlock interfaces
t-fork-enhance.c test npth fork interfaces
t-rwlock.c test npth rwlock interfaces
t-signal.c test npth signal interfaces
t-socket.c test npth socket interfaces
Signed-off-by: yaowenbin <yaowenbin1@huawei.com>
