target-counter and forced page break causes layout problems

[MurakamiShinyu]

When target-counter is used in a block that has forced page break with the next block, the following layout problems occurs:

• The block-start margin on the next block that begins the new page is ignored
  • Sample (JSBin): https://jsbin.com/kuluhig/edit?html,output
    • Test: https://vivliostyle.org/viewer/#src=https://jsbin.com/kuluhig
  • Related issue (closed): Top margin is ignored on a section with hard page break when target-counter is used #690
    • This issue was fixed by fix: top margin at forced break was ignored when target-counter is used #691 but that was an incomplete workaround; only fixed "break-before" case, and not fixed "break-after" case.
• The blank page selector does not match to the blank page.
  • See feat: support :blank page selector #721 (comment)