Fix various linting errors.

[barryhughes]

• Replay of PHPCS fixes: Squiz #1085
• Same commits.
• Seeing if a non-external PR gets through CI.

[barryhughes]

• Related: Update required PHP and platform PHP. #1088
• Let's rebase this one after the above is merged (assuming there are no unforeseen problems there).

[barryhughes]

• The same set of commits were already approved in PHPCS fixes: Squiz #1085
• This rebases them on trunk after the merge of some PHPUnit fixes made in Update required PHP and platform PHP. #1088
• Going ahead with a merge.