This is a fix/improvement for r23478 ("Fix disassembly redirection from stdout
into a file.").

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/554223002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23792 ce2b1a6d-e550-0410-aec6-3dcde31c8c00