Clean up some branching code by using presence

As I was working on the code to enable wemux, I noticed a few methods that could be shortened by the use of presence instead of checking for present? and then using it if it exists. https://github.com/rails/rails/blob/e20dd73df42d63b206d221e2258cc6dc7b1e6068/activesupport/lib/active_support/core_ext/object/blank.rb#L37