stack pointer to change by more than one in a corner case.  If we push
a constant smi larger than 16 bits, we push it via a temporary
register.  Allocating the temporary can cause a register to be spilled
from the frame somewhere above the stack pointer.

As a fix, do not use pushes to materialize ranges of elements of size
larger than one.

Review URL: http://codereview.chromium.org/92121

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1785 ce2b1a6d-e550-0410-aec6-3dcde31c8c00