CSS table omitting table-row element is not rendered correctly

[MurakamiShinyu]

Test case:

• https://gist.githubusercontent.com/MurakamiShinyu/c843e46282cbd51db234afec9fbc7631/raw/css-table-no-table-row.html

This test case is derived from the test "(20) No 'table-row' elements" in the existing test file packages/core/test/files/table/table_col_width.html. The test checks the rendering of a CSS table, not using HTML table elements but using CSS display: table, display: table-cell, etc., and omitting display: table-row elements for the first row (each cell contains "(1) …", "(2) …", …, "(13) …" lines) and the last row (each cell contains "Outside 'table-row'").

Test with canary viewer:

• https://vivliostyle.vercel.app/#src=https://gist.githubusercontent.com/MurakamiShinyu/c843e46282cbd51db234afec9fbc7631/raw/css-table-no-table-row.html

Problems:

1. "(13) Narrow col.", "(13) Long column. Long column.", "(13) Narrow col." disappear. These cell fragments are expected to be rendered on the top of page 2, but they are not rendered at all.
2. The top border of the cell "Outside 'table-row'" is not displayed.

Test with stable viewer:

• https://vivliostyle.org/viewer/#src=https://gist.githubusercontent.com/MurakamiShinyu/c843e46282cbd51db234afec9fbc7631/raw/css-table-no-table-row.html

"(13) …" is not displayed, same as canary. The top border of the cell "Outside 'table-row'" is displayed, different from canary. So the problem 1 is not a regression (this bug has been there since very old versions of Vivliostyle.js), but the problem 2 is a regression (PR #1665 is the most likely cause of the bug).

[MurakamiShinyu]

Problem 2 (The top border of the cell "Outside 'table-row'" is not displayed) is fixed by PR #1820.

Problem 1 ("(13) …" is not displayed) has not yet been fixed.