Fix ARM64 port after r22876.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/447443002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22879 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Revert "Unbreak build with clang."

This reverts commit r22878 and fixes the actual bug instead.

R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/446573002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22880 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Merge remote-tracking branch 'upstream/bleeding_edge' into bleeding_edge