message: NFC: Use Region::getBlocks to fix build failure with drop_begin.
diff: @@ -300,7 +300,7 @@ static LogicalResult deleteDeadness(MutableArrayRef<Region> regions,
  // Delete block arguments.
  // The entry block has an unknown contract with their enclosing block, so
  // skip it.
  - for (Block &block : llvm::drop_begin(region, 1)) {
  + for (Block &block : llvm::drop_begin(region.getBlocks(), 1)) {
  // Iterate in reverse to avoid shifting later arguments when deleting
  // earlier arguments.
  for (unsigned i = 0, e = block.getNumArguments(); i < e; i++)
  