message: simplify non-instruction blocks
diff: @@ -80,15 +80,10 @@ bool cannot_throw(cfg::Block* b) {
  }
  /*
  - * Return true if this is empty or only has positions in it
  + * Return true if the block does not contain any instruction.
  */
  bool is_effectively_empty(cfg::Block* b) {
  - for (const auto& mie : *b) {
  - if (mie.type != MFLOW_POSITION) {
  - return false;
  - }
  - }
  - return true;
  + return b->get_first_insn() == b->end();
  }
  /*
  