array_key_exists() micro-optimization

Problem/Motivation

isset() is fast but doesn't take in account NULL values, we can use it ahead of an array_key_exists() check to glean some of it's speed but PHP's short circuit ||
http://www.zomeoff.com/php-fast-way-to-determine-a-key-elements-existanc...

Proposed resolution

Before
if (array_key_exists($key, $array))

After
if (isset($array[$key]) || array_key_exists($key, $array))

Performance profiling

Scenario: 50 nodes generated on the homepage.

With warm cache but caches turned off with example.settings.local.php used.

After drush cr with the same.

Exceptions

If the array variable can potentially be an object without array access, array_key_exists() will ignore that but isset() will throw an Fatal Error in trying to use it as an array.
Example

// drush scr test.php
use Symfony\Component\HttpFoundation\ParameterBag;
$name = 'test';
$raw_parameters = new ParameterBag([$name => $name]);
if (isset($raw_parameters[$name]) && array_key_exists($name, $raw_parameters)) {
  print 'test';
}