Fix bug in test-code-stubs-x64 which meant not all registers were being checked.

Also change test-code-stubs-ia32 to use the same style as x64.

BUG=
R=danno@chromium.org

Review URL: https://codereview.chromium.org/22865006

Patch from Ross McIlroy <mcilroy@chromium.org>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16203 ce2b1a6d-e550-0410-aec6-3dcde31c8c00