Remove unused LOperands from keyed-loads. We do not have multiple representations
for load instructions anymore.

Correct number of output operands as for a couple of instructions form 1 to 0
because they do not produce a result (e.g. PushArgument)

Review URL: http://codereview.chromium.org/6158004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6258 ce2b1a6d-e550-0410-aec6-3dcde31c8c00