This switches out the existing constant splitting with masking that works like this:

1. Generate a random 32-bit value at compilation time.
2. XOR the 32-bit constant with the random value.
3. Emit the resulting immediate value along with the XOR operation to generate the original value.


BUG=http://code.google.com/p/v8/issues/detail?id=908

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5734 ce2b1a6d-e550-0410-aec6-3dcde31c8c00