[CodeGen] Print frame-setup/destroy flags in -debug output like we do in MIR

Currently the MachineInstr::print function prints the
frame-setup/frame-destroy differently than it does in MIR.

Instead of:

  %x21 = LDR %sp, -16; flags: FrameDestroy

print:

  %x21 = frame-destroy LDR %sp, -16

llvm-svn: 322088