Fix bug in control structures whitespace sniff triggered on last method of class

[jrfnl]

As reported here:

This rule does conflict with the WordPress.WhiteSpace.ControlStructureSpacing.BlankLineAfterEnd rule for the last method in a class if the function does not have a } // end myfunction() comment.
Still - the fact that it throws a message Blank line found after control structure when finding a blank line after the last method in a class might actually be a bug....

Added separate commits for unit test and fix to let travis demonstrate the bug and the fix.

[jrfnl]

Freaky weird that the bug is not triggered by the unit test when running this on travis. I can consistently reproduce this on my machine on several different PHP versions.

Edit: even weirder - it did trigger in the travis build for my fork: https://travis-ci.org/jrfnl/WordPress-Coding-Standards/builds/144630156

[jrfnl]

Rebased for merge conflict.