Unable to generate unsecure URL if current URL is secure

[apiuser]

Feature request from Marko-M, posted on GitHub Aug 16, 2016

Preconditions

1. Magento 2 version 2.1.0
2. Use \Magento\Framework\Url::getUrl() from secure area of the store

Steps to reproduce

1. Make sure code is executed in secure area of the store (HTTPS)
2. Generate URL in code

   /**
    * @var \Magento\Framework\Url
    */
   protected $url;
   ...
   $this->url->getUrl(
       'test/test/test',
       [
           '_secure' => false
       ]
   )

3. Resulting URL is https://example.com/test/test/test

Expected result

1. Make sure code is executed in secure area of the store (HTTPS)
2. Generate URL in code

   /**
    * @var \Magento\Framework\Url
    */
   protected $url;
   ...
   $this->url->getUrl(
       'test/test/test',
       [
           '_secure' => false
       ]
   )

3. Resulting URL is http://example.com/test/test/test

Reason behind such behavior is:

https://github.com/magento/magento2/blob/2.1.0/lib/internal/Magento/Framework/Url.php#L364-L366

where code assumes that if current request is secure, requested url should be secure as well, regardless to '_secure' parameter saying otherwise.