[laurentiu021]

Two deletes that acted on what they had seen earlier instead of what is there now.

What changes

• Shortcut Cleaner judges each ticked shortcut again before deleting it. DeleteShortcuts checked only that the .lnk was still there. The tab keeps the scan's list for the whole session and its rows arrive ticked, so a shortcut that worked again by the time of the delete, its program installed again and the shortcut rewritten at the same path, or a Recent item whose document was put back, was deleted anyway, permanently when Move to Recycle Bin was not ticked, after a confirmation that still called it broken. The scan's judgement of one shortcut is now JudgeShortcut, which both the scan and the delete use, OneDrive-shared folders included. A shortcut that works again is kept and returned in ShortcutDeletion.WorkAgain; the tab takes it off the list and adds "1 works again and was kept." to the status line. A shortcut the shell can no longer read is not shown to be broken and is left.
• Rebuild icon & thumbnail cache keeps a cache file's attributes. ExplorerShell.DeleteCacheFiles set each file to FileAttributes.Normal before deleting it, which replaces the whole set, so a database Explorer still held stayed on disk without Hidden and System. It clears only ReadOnly now, the attribute that blocks a delete, the way Deep Cleanup has since fix: one directory walk for every service that deletes what it finds #2382. ArchitectureTests.NoFileAttributesAreClearedBySettingThemToNormal reads the app's sources with comments stripped, first shows its pattern catches both the SetAttributes and the Attributes = forms, and fails on any use.
• README: the Shortcut Cleaner section says each shortcut is judged again before it goes.

How it was checked

• Without the re-check in DeleteShortcuts, AShortcutThatWorksAgain_IsKept_AndSaidToWorkAgain failed; with the COMException arm narrowed so it no longer catches, AShortcutTheShellCannotReadAgain_IsKept failed. The existing delete tests now hand in a judgement that keeps every shortcut broken and still pass unchanged otherwise.
• ShortcutCleanerRecheckTests.AShortcutWhoseProgramIsBackBeforeTheDelete_IsKept (integration) writes a real shortcut with the shell to a program in its own temp folder, scans it as broken, creates the program, and deletes: with the production re-check replaced by "always broken" it failed, the shortcut deleted.
• With FileAttributes.Normal back in DeleteCacheFiles, DeleteCacheFiles_AFileItCannotDelete_KeepsItsAttributes and the architecture test both failed.
• Unit suite twice, the format check, and all four projects built with no warnings.