List localhost first in /etc/hosts for 127.0.0.1 and ::1

This fixes https://github.com/travis-ci/travis-ci/issues/3054
Revert "List localhost first in /etc/hosts for 127.0.0.1 and ::1"

This reverts commit 95d3be1f4f63ad6e9c9a0669e77d3ba23be4b20f.
Add appliance to reorder aliases for 127.0.0.1 in /etc/hosts

Redo fix for https://github.com/travis-ci/travis-ci/issues/3054
Merge branch 'master' into ha-feature-dart-support-merge