net: add UV_TCP_REUSEPORT for tcp

[theanarkh]

SO_REUSEPORT allows users bind a port to multiple sockets, and incoming connections are distributed by OS across the listener sockets. It will improve the performance of server.

Refs: https://github.com/libuv/libuv/pull/4407

• [x] make -j4 test (UNIX), or vcbuild test (Windows) passes
• [x] tests and/or benchmarks are included
• [x] documentation is changed or added
• [x] commit message follows commit guidelines