Fix stale corcovado test module imports

Author: vcali

corcovado/test/mod.rs

@@ -12,10 +12,7 @@ extern crate fuchsia_zircon as zircon;
 
 pub use ports::localhost;
 
-mod test_close_on_drop;
 mod test_custom_evented;
-mod test_double_register;
-mod test_echo_server;
 mod test_local_addr_ready;
 mod test_multicast;
 mod test_oneshot;