[turbofan] Lower JSStoreProperty during JS typed lowering.

Note that we cannot yet emit a diamond here (patch is ready), because
the scheduler is still broken wrt. free floating control (seems related
although this diamond is not free floating).

TEST=cctest
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/557123005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23838 ce2b1a6d-e550-0410-aec6-3dcde31c8c00