* remove trailing spaces.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42406 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
range.c: return nil for empty range

* range.c (range_last): return nil for empty range, or in the case the
  predecessor is smaller than the begin.  [Bug #8739]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42407 b2dd03c8-39d4-4d8f-98ff-823fe69b080e