Remove not necessary file, move constants to the file they are used

File 'empty_bool.rb' was introduced around 4 years ago in
c10958fbddb22052e7cbe5fe6b825cda3cb26e48 to remove method redefined
warning in AS test suite, however we do not have such need for reuse
anymore, so we can safely move the constants back to the file where
they are currently used and get rid of the extra file/require.