Tame mjsunit/fast-literal after fixing allocations.

Not that allocations go through Heap::AllocateRaw and actually respect
the allocation timeout, the runtime of this test spiked. This adjusts
the limit to sane values now that the values are actually respected.

R=mvstanton@chromium.org
TEST=mjsunit/fast-literal

Review URL: https://codereview.chromium.org/63603009

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17615 ce2b1a6d-e550-0410-aec6-3dcde31c8c00