Deflake tcp_socket test.
Deflake tcp_socket test.

Increase the wait time for the thread to be blocked on read/write
syscall.

PiperOrigin-RevId: 342204627

google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor