Set max new space size in tests to proper MB value.

Revert "Limit old space size in test which require a large new space."

This reverts commit r21103.

Revert "Remove max space limits in tests."

This reverts commit r21104.

BUG=
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/263103006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21149 ce2b1a6d-e550-0410-aec6-3dcde31c8c00