[Bug #793](Closed) BigDecimal('Infinity').to_r が零になる

e$B%A%1%C%He(B #793 e$B$,99?7$5$l$^$7$?!#e(B (by Yukihiro M.)

e$B%9%F!<%?%9e(B Opene$B$+$ie(BClosede$B$KJQ99e(B

fixed by r20360.

http://redmine.ruby-lang.org/issues/show/793