Fix missing instruction in disassembler.
Fix wrong disassembly of multi-byte NOP on x64
Add test of disassembler on 64 bit!
Review URL: http://codereview.chromium.org/8773039

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10147 ce2b1a6d-e550-0410-aec6-3dcde31c8c00