ia32 and x64 more consistent now
1. use non-transcendental cache version of log for x64
2. use negative infinity constant instead of pushing to stack and loading to XMM register
3. remove movdbl, use movsd directly. movdbl seems confusing

BUG=
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/27197013

Patch from Weiliang Lin <weiliang.lin2@gmail.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17268 ce2b1a6d-e550-0410-aec6-3dcde31c8c00