code: public static boolean tryMergeBlock(Node block, boolean alwaysMerge) {
      checkState(block.isBlock());
      Node parent = block.getParent();
      boolean canMerge = alwaysMerge || canMergeBlock(block);
      // Try to remove the block if its parent is a block/script or if its
      // parent is label and it has exactly one child.
      if (isStatementBlock(parent) && canMerge) {
        Node previous = block;
        while (block.hasChildren()) {
          Node child = block.removeFirstChild();
          parent.addChildAfter(child, previous);
          previous = child;
        }
        parent.removeChild(block);
        return true;
      } else {
        return false;
      }
    }
docs: Merge a block with its parent block.
  @return Whether the block was removed.