cvt_l_d() and cvt_d_l() instructions are replaced to cvt_w_d() and ctv_d_w() because kernel FPU emulator generates illegal instruction for double <-> long conversions.

BUG=
R=jkummerow@chromium.org, plind44@gmail.com

Review URL: https://codereview.chromium.org/133363005

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19073 ce2b1a6d-e550-0410-aec6-3dcde31c8c00