Skip tests in nosnap mode.

Depends on https://codereview.chromium.org/230743002/.

BUG=v8:3216
LOG=n
R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/230583003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20618 ce2b1a6d-e550-0410-aec6-3dcde31c8c00