transformCommaExpression(tree) {
    let statements = tree.expressions.map((expr) => {
      if (expr.type === CONDITIONAL_EXPRESSION)
        return this.transformAny(expr);
      return createExpressionStatement(expr);
    });
    return new AnonBlock(tree.location, statements);
  }
Transformer for transforming a normalized comma expression as returned by the
ExplodeExpressionTransformer into a set of expression statements and if
statements.