Revert "linux: use CLOCK_{REALTIME,MONOTONIC}_COARSE"

This reverts r17642 (and follow-up fix r17644) for crashing the Chrome sandbox.

TBR=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/69933005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17668 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Fix usage of EmitBranch in compare-minus-zero-and-branch.

R=jkummerow@chromium.org
BUG=

Review URL: https://codereview.chromium.org/68933009

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17669 ce2b1a6d-e550-0410-aec6-3dcde31c8c00