1. Clean up the TargetMachine structure.  No more wierd pointers that have to
   be cast around and taken care of by the target.
2. Instruction Scheduling now takes the schedinfo as an argument.  The same
   should be done with the instinfo, it just isn't now.

llvm-svn: 565

llvm-svn: 563

llvm-svn: 562

llvm-svn: 561