Since SameValue algorithm is defined formally in ECMA262 and V8 already
exported Equals and StrictEquals algorithms, SameValue should be exposed.
And in this issue, we fix the issue of Object::SameValue implementation,
SameValue(0.0, -0.0) returnes true.

BUG=v8:2909
TEST=cctest/test-api/Equality
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/24360017

Patch from Yusuke Suzuki <yusukesuzuki@chromium.org>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16924 ce2b1a6d-e550-0410-aec6-3dcde31c8c00