message: Also print val for SourceBlocks
  Summary: As title
diff: @@ -1467,7 +1467,7 @@ std::ostream& operator<<(std::ostream& o, const MethodItemEntry& mie) {
  break;
  case MFLOW_SOURCE_BLOCK:
  o << "SOURCE-BLOCK: " << show(mie.src_block->src) << "@"
  - << mie.src_block->id;
  + << mie.src_block->id << "(" << mie.src_block->val << ")";
  break;
  case MFLOW_FALLTHROUGH:
  o << "FALLTHROUGH";
  