Check elimination now sets known successor branch of HCompareObjectEqAndBranch (correctness fix).

BUG=chromium:352058
LOG=N
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/196383018

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19964 ce2b1a6d-e550-0410-aec6-3dcde31c8c00