Don't disable hash randomization option in predictable mode.

We don't need it because
1) hash randomization uses random generator whose results depend on --random-seed option which is set in predictable mode.
2) disabling hash randomization triggers assert in snapshot mode.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/171813015

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19647 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Allow objects with "" properties to stay fast.

R=danno@chromium.org

Review URL: https://codereview.chromium.org/184453003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19648 ce2b1a6d-e550-0410-aec6-3dcde31c8c00