Re-enable disabled test.

build.rs

@@ -75,7 +75,6 @@ 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("My plain list implementation is currently broken."),
         _ => None,
     }
 }