Adds failing specs for indentation/alignment cops when chaining onto `end`
[Fix #670] Extract if/while from method chaining before checking it.

Chose to do a little bit of duplication between the two check_assignment
methods, since it would be weird for the rhs to not be the entire right
hand side of the assignment when check_assignment is called from the
CheckAssignment module.
Merge pull request #673 from jonas054/fix_indentation_when_chaining_on_end

Fix indentation when chaining on end