Revert "Active use of Hydrogen-generated generic KeyedLoad IC"

Due to mirror-object test failure (although I'm pretty sure I was framed)

R=mstarzinger@chromium.org
TBR=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/328333002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21812 ce2b1a6d-e550-0410-aec6-3dcde31c8c00