* numeric.c (flo_round): [EXPERIMENTAL] adjust the case that the
	  receiver is close to the exact but unrepresentable middle value
	  of two values in the given precision.
	  http://d.hatena.ne.jp/hnw/20160702

	numeric.c: round as double

	* numeric.c (flo_round): compare as double, not long double with
	  i387.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@58513 b2dd03c8-39d4-4d8f-98ff-823fe69b080e