[MachineOutliner] Check the last instruction from the sequence when updating liveness

The MachineOutliner was doing an std::for_each from the call (inserted
before the outlined sequence) to the iterator at the end of the
sequence.

std::for_each needs the iterator past the end, so the last instruction
was not taken into account when propagating the liveness information.

This fixes the machine verifier issue in machine-outliner-disubprogram.ll.

Differential Revision: https://reviews.llvm.org/D49295

llvm-svn: 337090