tools: Add bench tools for accept(2) and connect(2)

The main reasons behind making these tools instead of using netperf TCP_CC
test are:
- Netperf TCP_CC creates new server for each testing client
-

tools: Add bench tools for accept(2) and connect(2)

The main reasons behind making these tools instead of using netperf TCP_CC
test are:
- Netperf TCP_CC creates new server for each testing client
- Netperf TCP_CC creates new listen socket on different TCP port for each
testing client
- Netperf TCP_CC created listen socket is in blocking mode
- Netperf TCP_CC closes accepted sockets immediately

All of the above listed items make netperf TCP_CC do not reflect real life
TCP server usage.

Tools in accept_connect:
- "connect_client"
Fork certain amount of processes to perform blocking connect(2)/close(2)
for the certain amount of time.
- "accpet_server"
Fork certain amount of processes to perform blocking accept(2) on the same
addr/port bound socket. close(2) on the accepted socket is called
immediately. If -r is specified, each processes will create their own
listen socket on the same port/addr w/ SO_REUSEPORT sockopt.
- "kq_accept_server"
Fork certain amount of processes to perform non-blocking accept(2) on the
same addr/port bound socket w/ help of kqueue(2). close(2) on the accepted
socket is called after the other side closed the connection. If -r is
specified, each processes will create their own listen socket on the same
port/addr w/ SO_REUSEPORT sockopt.

kq_accept_server closely mimics the real life TCP server.

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