Grokdump -f: Automatically detect memory that is x86/x64 instructions or text and dump appropriately.
Review URL: https://chromiumcodereview.appspot.com/10356150

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11621 ce2b1a6d-e550-0410-aec6-3dcde31c8c00