doc: describe the local domain path on Windows

The UNIX domain is also known as the LOCAL domain (AF_LOCAL), and
node/libuv implements it on Windows using named pipes. The API
documentation did not describe the naming rules for named pipes, and
also repeatedly described `listen(path)` as being UNIX, which it is not
on Windows.

Closes #6743
deps: update http_parser to 2.2

Main changes:

* Added support for http statusMessage
http: parse the status message in a http response.
test: case insensitve path comparison on Windows

Windows needs case insensitive comparison when it comes to
path strings.
test: fix flaky unit test test-fs-realpath.js

The test was not performing proper cleanup and so it would
fail if run more than one time on the same machine.
events: move EE c'tor guts to EventEmitter.init

After landing 6ed861d it is no longer possible to reliably monkey-patch
the EventEmitter constructor. However there's valid use cases for that,
and makes for easier debugging. Therefore, move the guts of the
constructor to a separate function which is monkey-patchable.

Closes #6693
buffer: optimize writeInt* methods

Remove unnecessary encoding within writeInt*
tls: reintroduce socket.encrypted

Just a property that is always `true` for TLS sockets.

fix #6735
Revert "util: more strict check for bool/number/string"

This reverts commit 95ee84fabe0b028ef964cc1032cd56a6cf89cb0e.
util: introduce CHECK_EQ/CHECK_NE