Factored out the allocation in new space from assembler code into the macro assembler for x64 as was recently done for ia32.

Added set property svn:eol-style to native for all x64 files.
Review URL: http://codereview.chromium.org/173568

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2778 ce2b1a6d-e550-0410-aec6-3dcde31c8c00