Fix import manifest ordering: preserve topological sort from parser#16146

Copilot wants to merge 3 commits intocopilot/canonicalize-header-orderinggithub/gh-aw:copilot/canonicalize-header-orderingfrom

copilot/fix-tests-b76e9162-ba24-4aca-b836-d70ebbfec07egithub/gh-aw:copilot/fix-tests-b76e9162-ba24-4aca-b836-d70ebbfec07eCopy head branch name to clipboard