Noticing that the only difference between samevalue and strict equality is on
numbers we can simplify SameValue.
The old version did not return a correct answer if called on two strings since
StringEquals (from runtime.cc) returns an answer that is the negated value
(if treated as a boolean).
Review URL: http://codereview.chromium.org/2136024
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4713 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
