Slightly bump memory test limit for ia32 no-snapshot.

R=verwaest@chromium.org
TEST=cctest/test-mark-compact/BootUpMemoryUse

Review URL: https://codereview.chromium.org/12091088

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13568 ce2b1a6d-e550-0410-aec6-3dcde31c8c00