Tests were failing because the right permissions were not provided to iwasm.
Also, test failures didn't trigger build failure due to typo - also fixed in this change.
In addition to that, this PR fixes a few issues with the test itself:
* the `server_init_complete` was not reset early enough causing the client to occasionally
assume the server started even though it didn't yet
* set `SO_REUSEADDR` on the server socket so the port can be reused shortly after
closing the previous socket
* defined receive-send-receive sequence from server to make sure server is alive at the
time of sending message