Don't record instructions for copying method arguments in the

Don't record instructions for copying method arguments in the
AddedInstrns sets for the first machine instruction.  It is hard
to ensure that the right order is preserved, and sure enough, the
order was broken.  Instead, use a separate set for the function entry.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2312 91177308-0d34-0410-b5e6-96231b3b80d8