* bignum.c (big_shift3): New function.
  big_lshift and big_rshift are merged.
  (big_shift2): New function.
  (big_lshift): Use big_shift3.
  (big_rshift): Ditto.
  (check_shiftdown): Removed.
  (rb_big_lshift): Use big_shift2 and big_shift3.
  (rb_big_rshift): Ditto.
  (big_lshift): Removed.
  (big_rshift): Ditto.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41942 b2dd03c8-39d4-4d8f-98ff-823fe69b080e