[x64] add disasm for two fp instructions

BUG=
R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/146583002

Patch from Weiliang Lin <weiliang.lin@intel.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19022 ce2b1a6d-e550-0410-aec6-3dcde31c8c00