This is supposed to be a mechanical change with no functional effects.
InstrEmitter can generate all types of MachineOperands which revealed
that MachineInstrBuilder was missing a few methods, added by this patch.
Besides providing a context pointer to MI::addOperand(),
MachineInstrBuilder seems like a better fit for this code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170712 91177308-0d34-0410-b5e6-96231b3b80d8