This reverts commit r23205.

Setting string-type flags in unit tests is not a good idea.

TBR=titzer@chromium.org

Review URL: https://codereview.chromium.org/489543002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23208 ce2b1a6d-e550-0410-aec6-3dcde31c8c00