message: Clean-up: simplify reshape functions in tree_unwrapper
  No functional change.
  issues
diff: @@ -928,27 +928,13 @@ static void AttachTrailingSemicolonToPreviousPartition(
  static void ReshapeIfClause(const SyntaxTreeNode& node,
  TokenPartitionTree* partition_ptr) {
  - const auto tag = NodeEnum(node.Tag().tag);
  auto& partition = *partition_ptr;
  - if (tag == NodeEnum::kIfClause) {
  - const auto& body = GetSubtreeAsNode(node, tag, 1, NodeEnum::kIfBody);
  - if (body.children().size() != 1) return;
  - if (!GetSubtreeAsNode(body, NodeEnum::kIfBody, 0)
  - .MatchesTag(NodeEnum::kSeqBlock)) {
  - VLOG(4) << "if-body was not a begin-end block.";
  - return;
  - }
  - } else {
  - CHECK_EQ(tag, NodeEnum::kGenerateIfClause);
  - const auto& body =
  - GetSubtreeAsNode(node, tag, 1, NodeEnum::kGenerateIfBody);
  - if (body.children().size() != 1) return;
  - if (!GetSubtreeAsNode(body, NodeEnum::kGenerateIfBody, 0)
  - .MatchesTag(NodeEnum::kGenerateBlock)) {
  + const SyntaxTreeNode& body =
  + *ABSL_DIE_IF_NULL(GetAnyControlStatementBody(node));
  + if (!NodeIsBeginEndBlock(body)) {
  VLOG(4) << "if-body was not a begin-end block.";
  return;
  }
  - }
  // Then fuse the 'begin' partition with the preceding 'if (...)'
  auto& if_body_partition = partition.Children().back();
  @@ -963,16 +949,11 @@ static void ReshapeIfClause(const SyntaxTreeNode& node,
  static void ReshapeElseClause(const SyntaxTreeNode& node,
  TokenPartitionTree* partition_ptr) {
  - const auto tag = NodeEnum(node.Tag().tag);
  auto& partition = *partition_ptr;
  - const SyntaxTreeNode* else_body_subnode;
  - if (tag == NodeEnum::kGenerateElseClause) {
  - else_body_subnode = &GetElseClauseGenerateBody(node);
  - } else {
  - CHECK_EQ(tag, NodeEnum::kElseClause);
  - else_body_subnode = &GetElseClauseStatementBody(node);
  - }
  - if (!NodeIsConditionalOrBlock(*else_body_subnode)) {
  + const SyntaxTreeNode& else_body_subnode =
  + *ABSL_DIE_IF_NULL(GetAnyControlStatementBody(node));
  + if (!NodeIsConditionalOrBlock(else_body_subnode)) {
  + VLOG(4) << "else-body was neither a begin-end block nor if-conditional.";
  return;
  }
  @@ -1354,9 +1335,8 @@ void TreeUnwrapper::ReshapeTokenPartitions(
  case NodeEnum::kFinalStatement: {
  // In these cases, merge the 'begin' partition of the statement block
  // with the preceding keyword or header partition.
  - if (verible::SymbolCastToNode(*node.children().back())
  - .MatchesTagAnyOf(
  - {NodeEnum::kSeqBlock, NodeEnum::kGenerateBlock})) {
  + if (NodeIsBeginEndBlock(
  + verible::SymbolCastToNode(*node.children().back()))) {
  auto& seq_block_partition = partition.Children().back();
  VLOG(4) << "block partition: " << seq_block_partition;
  auto& begin_partition = *seq_block_partition.LeftmostDescendant();
  