message: Ignore function-local OpUndef for stepping
diff: @@ -575,7 +575,7 @@ void ThreadState::SkipIgnoredInstructions()
  {
  Iter it = debugger.GetIterForInstruction(nextInstruction);
  rdcspv::Op op = it.opcode();
  - if(op == Op::Line || op == Op::NoLine)
  + if(op == Op::Line || op == Op::NoLine || op == Op::Undef)
  {
  nextInstruction++;
  continue;
  