ExtUvLoop: Fix reporting connection refused errors

[clue]

This PR fixes reporting "connection refused" on affected installation of ExtUvLoop. I have started with adding relevant tests to the test matrix, fixing the underlying issue and included additional tests to run run this on Windows as well.

Resolves#188
Builds on top of #205
Refs #206 to skip a similar problem for the StreamSelectLoop on Windows only.

[clue]

It works! 🎉

The underlying epoll_wait() reports EPOLLOUT|EPOLLERR|EPOLLHUP on
the affected file descriptor, which ext-uv emits as an error code
EBADF with no events attached. We explicitly re-enable all active
events on this error event to invoke the writable listener for this
condition to match other event loop implementations and successfully
detect this as a refused connection attempt. All tests are now green.

For future reference, here's how to install this extension in a sample Docker container and all the commands I've used to debug this issue:

docker run -it -v /home/me/workspace:/workspace --workdir=workspace ubuntu:latest bash
apt update
apt-get install -y software-properties-common
add-apt-repository ppa:ondrej/php -y
apt-get install -y libuv1-dev php-pear php-dev strace
pecl install uv-beta
echo"extension=uv">>"$(php -r 'echo php_ini_loaded_file();')"
php -m
cd /workspace
strace php examples/14-http-client-async.php
php -r 'var_dump((new ReflectionClass("UV"))->getConstants());'
vendor/bin/phpunit

• http://man7.org/linux/man-pages/man2/epoll_ctl.2.html

Now let's get this shipped!

[WyriHaximus]

🎉