potentially leading to bogus FatalProcessOutOfMemory situations.  Also
fixed a few cases where callers relied on getting a NewSpace object
back (to avoid write barrier overhead) which they can't when
always_allocate is in effect.

Review URL: http://codereview.chromium.org/391018


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3285 ce2b1a6d-e550-0410-aec6-3dcde31c8c00