* gc.c: use oldgen bitmap as initial mark bitmap when mijor gc.
	  so can skip oldgen bitmap check around mark & sweep.
	* gc.c (slot_sweep_body): change scan algorithm for performance:
	  from object's pointer base to bitmap one.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41128 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* remove trailing spaces.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41129 b2dd03c8-39d4-4d8f-98ff-823fe69b080e