Fix issues with code serializer.

- code pre-aging does not work with serializing.
- compilation info needs to remember that we compile for serializing.
- test case leaks memory.

R=vogelheim@chromium.org

Review URL: https://codereview.chromium.org/379563002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22281 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Reland r22247 "ARM64: Use UntagSmi helpers and clean up assertions."

BUG=
R=ulan@chromium.org

Review URL: https://codereview.chromium.org/371033002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22282 ce2b1a6d-e550-0410-aec6-3dcde31c8c00