Revert "Unify the Count Operation assignment with other assignments."

This reverts commit r15578.

This change made mjsunit/harmony/object-observe.js flaky.

TBR=verwaest@chromium.org

Review URL: https://codereview.chromium.org/18537006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15580 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Fix plot script.

The script for the time line plot has been broken since r15484, which
changed the format of tick entries in v8.log.

To prevent this from happening in the future, I added a test case.

R=hpayer@chromium.org
BUG=

Review URL: https://codereview.chromium.org/18826008

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15581 ce2b1a6d-e550-0410-aec6-3dcde31c8c00