bignum.c: adjust condtions
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45330 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
bignum.c: adjust condtions
condtions to maxpow_in_bdigit_dbl().
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45330 b2dd03c8-39d4-4d8f-98ff-823fe69b080e