Command app:config:dump add unnecessary spacing every time it's run

[Linek]

Preconditions

1. PHP 7.0.24
2. nginx/1.11.13
3. Percona Ver 14.14 Distrib 5.7.19-17
4. Magento 2.2.0 installed with sample data by composer

Steps to reproduce

1. Run "bin/magento app:config:dump" to dump configuration to app/etc/config.php file
2. Save your config.php file somewhere to compare
3. Run "bin/magento app:config:dump" again
4. Compare config.php after second dump with the one after first dump

Expected result

File config.php should not change when there is no modification in configuration

Actual result

Every time app:config:dump is run few fields is generated with additional spaces

List of fields:
default_custom_instructions
minify_exclude
address_templates

[davidalger]

Closing as duplicate of #11328; fixed in 2.1-develop, there are PRs in progress for 2.2 and 2.3 to apply the same fix.