Broken logic for `https_local_ssl_verify` filter due to missing `local` argument

[johnbillion]

When the Requests library was merged in WP 4.6, the local element in the $args array of an HTTP API request was removed. The logic for the https_local_ssl_verify filter relies on this argument being present and therefore doesn't behave properly.

To reproduce, perform an HTTP API request to home_url() and verify that the https_local_ssl_verify filter does not get triggered.

Introduced in [37428].

Trac Ticket: Core-51767

## Issue

In WordPress 4.6, the $args['local'] element was removed from HTTP API requests, which caused the https_local_ssl_verify filter to malfunction.

## Solution

This update restores the expected behaviour by checking if a request is local using:

• The REMOTE_ADDR (127.0.0.1, ::1).

• The HTTP_HOST (localhost, 127.0.0.1).

This has nothing to do with the _current_ request, only the HTTP API request being performed.

[pmbaldha]

@johnbillion Should we remove the https_local_ssl_verify filter logic from ​https://github.com/WordPress/wordpress-develop/blob/trunk/src/wp-includes/class-wp-http-curl.php#L122?