This change introduces LTemplateInstruction which is a specialized version
of LInstruction and takes one template parameter to indicate whether the
instruction produces a result operand.

All instruction that do not have a result inherit from LTemplateInstruction<0>.
Instructions that have a result operand from LTemplateInstruction<1>

All the Define* function only operate on instructions with a result.

For this to work I also refactored the places where we do 

  LInstruction* result = new Lxyy

into

  Lxyz* result = new Lxyz 



Review URL: http://codereview.chromium.org/6219001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6245 ce2b1a6d-e550-0410-aec6-3dcde31c8c00