Put all trailing whitespace ownership test cases into the automated tests.

Notes for this investigation moved to cba1d1e988/notes/plain_list_ownership_notes.org .

Mailing list thread on the investigation: https://list.orgmode.org/9372527e-3852-419e-936a-7b4dd38cc847@app.fastmail.com/ .

build.rs

@@ -75,7 +75,9 @@ fn is_expect_fail(name: &str) -> Option<&str> {
         "element_container_priority_footnote_definition_dynamic_block" => Some("Apparently broken begin lines become their own paragraph."),
         "paragraphs_paragraph_with_backslash_line_breaks" => Some("The text we're getting out of the parse tree is already processed to remove line breaks, so our comparison needs to take that into account."),
         "export_snippet_paragraph_break_precedence" => Some("The latest code for org-mode is matching the export snippet without the closing @@."), // https://list.orgmode.org/orgmode/fb61ea28-f004-4c25-adf7-69fc55683ed4@app.fastmail.com/T/#u
-        "plain_lists_trailing_whitespace_ownership" => Some("Seeing odd behavior about whitespace ownership."),
+        "plain_lists_trailing_whitespace_ownership_test_case_1" => Some("Seeing odd behavior about whitespace ownership."), // https://list.orgmode.org/9372527e-3852-419e-936a-7b4dd38cc847@app.fastmail.com/
+        "plain_lists_trailing_whitespace_ownership_test_case_3" => Some("Seeing odd behavior about whitespace ownership."), // https://list.orgmode.org/9372527e-3852-419e-936a-7b4dd38cc847@app.fastmail.com/
+        "plain_lists_trailing_whitespace_ownership_test_case_4" => Some("Seeing odd behavior about whitespace ownership."), // https://list.orgmode.org/9372527e-3852-419e-936a-7b4dd38cc847@app.fastmail.com/
         _ => None,
     }
 }