Instead of constructing a temporary container for all LOperands of each
instruction, the register works directly on the LIR instructions that
 provide an abstract interface for input/output/temp operands.

This saves allocation of zone memory and speeds up LIR construction,
but makes iterating over all uses in the register allocator slightly
more expensive because environment uses are stored in a linked list of
environments. We can fix this by using a flat representation of LOperands.


Review URL: http://codereview.chromium.org/6352006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6638 ce2b1a6d-e550-0410-aec6-3dcde31c8c00