Remove unused MachineInstr constructors.

A MachineInstr can only ever be constructed by CreateMachineInstr() and
CloneMachineInstr(), and those factories don't use the removed
constructors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169395 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed