Fix bug in sharing code.  When choosing the object to retain out of a number with the same contents, pick one in an immutable area rather than the allocation area.  Otherwise the invariant that immutable areas never point into the allocation area could be broken.  The bug was introduced by #1430 which removed the FullGC call that had ensured that there was no data in the allocation areas.
Fix bug in sharing code.  When choosing the object to retain out of a number with the same contents, pick one in an immutable area rather than the allocation area.  Otherwise the invariant that immutable areas never point into the allocation area could be broken.  The bug was introduced by #1430 which removed the FullGC call that had ensured that there was no data in the allocation areas.

git-svn-id: 98787b36aaefbae4b30fa755be920954cd25e1e4@1451 ae7d391e-3f74-4a2b-a0db-a8776840fd2a

mn200/polyml,polyml/polyml,polyml/polyml,mn200/polyml,dcjm/polyml,dcjm/polyml,mn200/polyml,dcjm/polyml,mn200/polyml,dcjm/polyml,polyml/polyml,polyml/polyml